<PAGE>

                       Securities and Exchange Commission
                             Washington, D.C. 20549

                                    FORM 10-K

             [ X ] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934

                   For the fiscal year ended December 31, 1999
                                       OR
            [ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934

             For the transition period from            to
                                           -----------     ----------


                         Commission File number 0-17721

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                    (Exact name of registrant as specified i
                     its Certificate of Limited Partnership)

         TEXAS                                       76-0261832
(State of Organization)                   (I.R.S. Employer Identification No.)


                         16825 Northchase Dr., Suite 400
                              Houston, Texas 77060
                                 (281) 874-2700
          (Address and telephone number of principal executive offices)


           Securities registered pursuant to Section 12(b) of the Act:
                                      None

           Securities registered pursuant to Section 12(g) of the Act:
                       51,090.57 Limited Partnership Units

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the  preceding 12 months (or for such shorter  periods that the  registrant  was
required),  and (2) has been subject to such filing requirements for the past 90
days.

                             Yes   X   No
                                 -----    -----

Indicate by check mark if disclosure of delinquent  filers  pursuant to Item 405
of Regulation  S-K is not contained  herein,  and will not be contained,  to the
best of registrant's  knowledge,  in definitive proxy or information  statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [ X ]

Registrant does not have an aggregate  market value for its Limited  Partnership
Interests.

                       Documents Incorporated by Reference

Document                                             Incorporated as to

    Registration Statement No. 33-11773                Items 1 and 13
     on Form S-1


<PAGE>


                                TABLE OF CONTENTS
                             Form 10-K Annual Report
                     For the Period Ended December 31, 1999

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
<TABLE>
<CAPTION>
ITEM NO.                                            PART I                          PAGE
--------                                            ------                          ----
   <S>                     <C>                                                      <C>
   1                       Business                                                   I-1
   2                       Properties                                                 I-5
   3                       Legal Proceedings                                          I-7
   4                       Submission of Matters to a Vote of
                             Security Holders                                         I-7


                                                     PART II
                                                     -------
   5                       Market Price of and Distributions on the
                             Registrant's Units and Related Limited
                             Partner Matters                                         II-1
   6                       Selected Financial Data                                   II-2
   7                       Management's Discussion and Analysis of
                             Financial Condition and Results of Operations           II-2
   8                       Financial Statements and Supplementary Data               II-4
   9                       Disagreements on Accounting and Financial
                             Disclosure                                              II-4


                                                     PART III
                                                     --------
  10                       Directors and Executive Officers of the
                             Registrant                                             III-1
  11                       Executive Compensation                                   III-2
  12                       Security Ownership of Certain Beneficial
                             Owners and Management                                  III-2
  13                       Certain Relationships and Related Transactions           III-2


                                                     PART IV
                                                     -------
  14                       Exhibits, Financial Statement Schedules
                             and Reports on Form 8-K                                 IV-1


                                                     OTHER
                                                     -----
                           Signatures
</TABLE>


<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

                                     PART I

Item 1.  Business

General Description of Partnership

         Swift Energy Income Partners 1988-C,  Ltd., a Texas limited partnership
(the "Partnership" or the "Registrant"),  is a partnership formed under a public
serial limited partnership offering denominated Swift Energy Income Partners III
(Registration  Statement No. 33-11773 on Form S-1, originally declared effective
March 19, 1987,  and amended  effective  March 28, 1988,  May 4, 1989 and May 1,
1990 [the  "Registration  Statement"]).  The  Partnership  was formed  effective
October 3, 1988 under a Limited Partnership  Agreement dated September 30, 1988.
The initial 535 limited partners made capital contributions of $5,109,057.

         The  Partnership is  principally  engaged in the business of acquiring,
developing and, when  appropriate,  disposing of working interests in proven oil
and gas properties  within the continental  United States.  The Partnership does
not  engage  in  exploratory  drilling.   Each  working  interest  held  by  the
Partnership entitles the Partnership to receive, in kind or in value, a share of
the  production  of oil and gas from the producing  property,  and obligates the
Partnership  to  participate  in the  operation  of the property and to bear its
proportionate share of all operating costs associated therewith. The Partnership
typically  holds  less  than  the  entire  working  interest  in  its  producing
properties.

         At December  31,  1999,  the  Partnership  had expended or committed to
expend 100% of the limited  partners' net commitments  (i.e.,  limited partners'
commitments available to the Partnership for property acquisitions after payment
of  organization  fees and  expenses)  in the  acquisition  and  development  of
producing properties, which properties are described under Item 2, "Properties,"
below. The  Partnership's  revenues and profits are derived almost entirely from
the  sale of oil and gas  produced  from  its  properties  and  from the sale of
acquired  oil  and  gas  properties,   when  the  sale  of  such  properties  is
economically preferable to continued operation.

         The  Partnership's  business and affairs are  conducted by its Managing
General  Partner,  Swift Energy  Company,  a Texas  corporation  ("Swift").  The
Partnership's Special General Partner, VJM Corporation, a California corporation
("VJM"),  consults with and advises Swift as to certain financial matters. Swift
is the designated  operator of many of the  properties in which the  Partnership
owns  interests.  The remaining  properties  are operated by industry  operators
designated by the owners of a majority of the working interest in each property.

         The  general  manner  in  which  the  Partnership   acquires  producing
properties  and  otherwise  conducts  its business is described in detail in the
Registration Statement under "Proposed Activities," which is incorporated herein
by reference.  The following is intended only as a summary of the  Partnership's
manner of doing business and specific activities to date.

Liquidation

         During the first quarter of 2000, the Managing  General  Partner mailed
proxy material to the limited partners  proposing to sell all the  Partnership's
interests in oil and gas properties and dissolve and liquidate the  Partnership.
If this proosal is  approved,  it is  anticipated  that the  liquidation  of the
Partnershi will be substantially completed withing the next two years.

Manner of Acquiring  Properties;  Net Profits and  Overriding  Royalty  Interest
Agreement

         For the sake of legal and  administrative  convenience,  the  producing
properties  owned by the Registrant  have  typically been acquired  initially by
Swift,  which then conveyed  ownership of each such property to the  Registrant.
The  Registrant  acquires  producing  properties  from  Swift  at  the  property
acquisition  cost of such  properties  to Swift,  as  adjusted  for  intervening
operations.

         The  Registrant  entered  into a Net  Profits  and  Overriding  Royalty
Interest  Agreement  dated October 18, 1988 (the "NP/OR  Agreement")  with Swift
Energy  Managed   Pension  Assets   Partnership   1988-B,   Ltd.  (the  "Pension
Partnership").  The Pension  Partnership is a Texas limited  partnership that is
also  managed by Swift and VJM.  The Pension  Partnership  was formed to acquire
nonoperating  interests,  such as net profits,  royalty and  overriding  royalty
interests, in producing oil and gas properties.

                                      I-1


<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

         Under the NP/OR Agreement,  the Registrant and the Pension  Partnership
have, in effect,  combined their funds in acquiring producing properties;  using
funds  committed to the NP/OR  Agreement by both  partnerships,  the  Registrant
acquires  producing  properties,  then promptly conveys  nonoperating  interests
therein  to  the  Pension   Partnership.   The  Registrant  initially  committed
$4,647,380  and the  Pension  Partnership  initially  committed  $3,118,567  for
acquisitions  under the NP/OR  Agreement.  The Registrant is obligated under the
NP/OR  Agreement  to convey to the Pension  Partnership  a 40% fixed net profits
interest and a variable overriding royalty interest in specified depths of every
producing  property it  acquires,  except  that (i)  properties  anticipated  to
require  significant  development  operations,  and (ii) nonoperating  interests
offered to the  Registrant by third  parties may be purchased by the  registrant
outside the NP/OR Agreement,  without  participation by the Pension Partnership.
The  Registrant is entitled to withdraw up to 30% of its  committed  funds under
the NP/OR Agreement for such acquisitions.

         All properties  acquired by the Registrant  since the date of the NP/OR
Agreement have been acquired subject to the NP/OR Agreement and the nonoperating
interests created thereby,  except for certain  nonoperating  interests acquired
outside  the  NP/OR  Agreement  by the  Registrant  from  Northwind  Exploration
Company.  At December 31, 1999, the  Registrant had not made any  withdrawals to
acquire properties anticipated to require significant development.

         In accordance with its  obligations  under the NP/OR  Agreement,  as of
December 31, 1999, the Registrant had conveyed to the Pension  Partnership a net
profits interest  burdening  certain depths of all producing  properties  (other
than the Northwind  properties) acquired by the Registrant since the date of the
NP/OR  Agreement.  Typically,  a net profits interest in an oil and gas property
entitles  the  owner  to a  specified  percentage  share of the  gross  proceeds
generated by the burdened property,  net of operating costs. The 40% net profits
interest  conveyed to the Pension  Partnership under the NP/OR Agreement differs
from the typical net profits  interest in that it is calculated  over the entire
group of producing  properties  acquired  under the NP/OR  Agreement;  i.e., all
operating  costs  attributable  to the burdened  depths of such  properties  are
aggregated,  and the  total  is then  subtracted  from the  total  of all  gross
proceeds  attributable  to such depths in order to calculate  the net profits to
which the Pension Partnership is entitled.  The net profits interest conveyed to
the Pension Partnership burdens only those depths of each subject property which
were evaluated to contain  proved  reserves at the date of  acquisition,  to the
extent such depths underlie specified surface acreage.

         The Registrant has also conveyed to the Pension  Partnership  under the
NP/OR Agreement an overriding  royalty interest in each property (other that the
Northwind  properties)  acquired  since  the  date of the  NP/OR  Agreement.  An
overriding royalty interest is a fractional interest in the gross production (or
the  gross  proceeds  therefrom)  of oil and gas  from a  property,  free of any
exploration,  development,  operation or maintenance  expenses.  Under the NP/OR
Agreement,  the  overriding  royalty  interest  burdens  the  portions  of  each
producing property that were evaluated at the date of acquisition not to contain
proved reserves.

Competition, Markets and Regulations

         Competition

         The oil and gas industry is highly  competitive in all its phases.  The
Partnership encounters strong competition from many other oil and gas producers,
many of which possess substantial financial resources, in acquiring economically
desirable Producing Properties.

         Markets

         The amounts of and price  obtainable  for oil and gas  production  from
Partnership  Properties will be affected by market factors beyond the control of
the  Partnership.  Such factors include the extent of domestic  production,  the
level of imports of foreign oil and gas, the general level of market demand on a
regional, national and worldwide basis, domestic and foreign economic conditions
that  determine  levels of industrial  production,  political  events in foreign
oil-producing  regions, and variations in governmental  regulations and tax laws
and  the  imposition  of new  governmental  requirements  upon  the  oil and gas
industry. There can be no assurance that oil and gas prices will not decrease in
the future, thereby decreasing net Revenues from Partnership Properties.

         From time to time,  there may exist a  surplus  of  natural  gas or oil
supplies,  the effect of which may be to reduce the amount of hydrocarbons  that
the  Partnerships may produce and sell while such oversupply  exists.  In recent
years,  initial steps have been taken to provide  additional gas  transportation
lines from Canada to the United States. If additional Canadian gas is brought to
the United States market, it could create downward pressure on United States gas
prices.

                                      I-2

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

         Regulations

         Environmental Regulation

         The federal  government  and various state and local  governments  have
adopted  laws and  regulations  regarding  the control of  contamination  of the
environment.  These laws and regulations may require the acquisition of a permit
by Operators before drilling commences,  prohibit drilling activities on certain
lands  lying  within  wilderness  areas or where  pollution  arises  and  impose
substantial  liabilities for pollution  resulting from operations,  particularly
operations near or in onshore and offshore waters or on submerged  lands.  These
laws and  regulations  may also  increase  the  costs of  routine  drilling  and
operation of wells.  Because these laws and regulations change  frequently,  the
costs to the  Partnership of compliance  with existing and future  environmental
regulations cannot be predicted.  However, the Managing Partner does not believe
that the  Partnership is affected in a significantly  different  manner by these
regulations than are its competitors in the oil and gas industry.

         Federal Regulation of Natural Gas

         The  transportation  and sale of natural gas in interstate  commerce is
heavily  regulated  by  agencies  of  the  federal  government.   The  following
discussion is intended only as a summary of the principal statutes,  regulations
and  orders  that  may  affect  the  production  and  sale of  natural  gas from
Partnership  Properties.  This  summary  should not be relied upon as a complete
review of applicable natural gas regulatory provisions.

         FERC Orders

         Several major  regulatory  changes have been implemented by the Federal
Energy Regulatory  Commission  ("FERC") from 1985 to the present that affect the
economics of natural gas production,  transportation and sales. In addition, the
FERC  continues  to  promulgate  revisions  to various  aspects of the rules and
regulations  affecting  those  segments of the natural gas industry  that remain
subject to the FERC's jurisdiction. In April 1992, the FERC issued Order No. 636
pertaining to pipeline restructuring. This rule requires interstate pipelines to
unbundle  transportation  and sales services by separately  stating the price of
each service and by providing  customers  only the particular  service  desired,
without  regard to the source for  purchase of the gas.  The rule also  requires
pipelines to (i) provide  nondiscriminatory  "no-notice"  service  allowing firm
commitment  shippers to receive  delivery of gas on demand up to certain  limits
without  penalties,  (ii) establish a basis for release and reallocation of firm
upstream  pipeline  capacity  and  (iii)  provide  non-discriminatory  access to
capacity by firm  transportation  shippers on a  downstream  pipeline.  The rule
requires interstate  pipelines to use a straight fixed variable rate design. The
rule imposes these same requirements upon storage facilities.

         FERC Order No. 500  affects the  transportation  and  marketability  of
natural gas.  Traditionally,  natural gas has been sold by producers to pipeline
companies,  which then  resold the gas to  end-users.  FERC Order No. 500 alters
this market structure by requiring  interstate  pipelines that transport gas for
others to provide  transportation  service to  producers,  distributors  and all
other shippers of natural gas on a nondiscriminatory, "first-come, first-served"
basis ("open access  transportation"),  so that producers and other shippers can
sell natural gas directly to end-users.  FERC Order No. 500 contains  additional
provisions intended to promote greater competition in natural gas markets.

         It is not anticipated  that the  marketability  of and price obtainable
for natural gas production from  Partnership  Properties  will be  significantly
affected  by FERC  Order No.  500.  Gas  produced  from  Partnership  Properties
normally  will be sold to  intermediaries  who have entered into  transportation
arrangements with pipeline companies.  These  intermediaries will accumulate gas
purchased from a number of producers and sell the gas to end-users  through open
access pipeline transportation.

         State Regulations

         Production  of any oil  and gas  from  Partnership  Properties  will be
affected  to some  degree  by  state  regulations.  Many  states  in  which  the
Partnership will operate have statutory provisions regulating the production and
sale  of oil  and  gas,  including  provisions  regarding  deliverability.  Such
statutes, and the regulations promulgated in connection therewith, are generally
intended to prevent  waste of oil and gas and to protect  correlative  rights to
produce  oil and  gas  between  owners  of a  common  reservoir.  Certain  state
regulatory  authorities  also  regulate  the amount of oil and gas  produced  by
assigning allowable rates of production to each well or proration unit.

                                      I-3

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

         Federal Leases

         Some of the Partnership's properties are located on federal oil and gas
leases  administered by various federal  agencies,  including the Bureau of Land
Management.   Various  regulations  and  orders  affect  the  terms  of  leases,
exploration and development plans, methods of operation and related matters.

         Employees

         The  Partnership  has no  employees.  Swift,  however,  has a staff  of
geologists,   geophysicists,   petroleum  engineers,   landmen,  and  accounting
personnel who  administer  the  operations of Swift and the  Partnership.  As of
December 31, 1999, Swift had 173 employees.  Swift's administrative and overhead
expenses  attributable  to  the  Partnership's   operations  are  borne  by  the
Partnership.

                                      I-4

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

Item 2.  Properties

         As of December  31, 1999,  the  Partnership  has acquired  interests in
producing oil and gas properties which are generally described below.

Principal Oil and Gas Producing Properties

         The most  valuable  fields  in the  Partnership,  based  upon  year-end
engineering  estimates of discounted  future net revenues using constant pricing
and costs, are described below.

         1.  The  Grapeland  Field  is  in  Houston  County,   Texas  (Grapeland
acquisition). This field represents 28% of the Partnership's value.

         2. The AWP  Field is in  McMullen  County,  Texas  (Shell  Oil  Company
acquisition). The wells produce from the Olmos formation,  accounting for 21% of
the value.

         The remaining  value in the  Partnership  is  attributable  to numerous
properties  none of which equals or exceeds 15 percent of the total  Partnership
value.

Title to Properties

         Title to  substantially  all  significant  producing  properties of the
Partnership has been examined. The properties are subject to royalty, overriding
royalty and other  interests  customary in the  industry.  The Managing  General
Partner does not believe any of these burdens  materially detract from the value
of the properties or will materially detract from the value of the properties or
materially  interfere  with their use in the  operation  of the  business of the
Partnership.

Production and Sales Price

         The following table  summarizes the sales volumes of the  Partnership's
net oil and gas production  expressed in MCFs.  Equivalent  MCFs are obtained by
converting oil to gas on the basis of their relative energy content;  one barrel
equals 6,000 cubic feet of gas.

<TABLE>
<CAPTION>
                                                                    Net Production
                                                     ------------------------------------------
                                                                 For the Years Ended
                                                                    December 31,
                                                     ------------------------------------------
                                                      1999             1998              1997
                                                     ------           -------           -------
<S>                                                  <C>               <C>              <C>
Net Volumes (Equivalent MCFs)                        65,913            90,442           123,886

Average Sales Price
   per Equivalent MCF                                $2.23             $1.77            $2.52

Average Production Cost
   per Equivalent MCF
   (includes production taxes)                       $0.82             $0.82            $0.73
</TABLE>

                                      I-5

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

Net Proved Oil and Gas Reserves

         Presented below are the estimates of the Partnership's  proved reserves
as of December 31, 1999, 1998 and 1997. All of the Partnership's proved reserves
are located in the United States.
<TABLE>
<CAPTION>

                                                                      December 31,
                                    -------------------------------------------------------------------------------
                                             1999                          1998                        1997
                                    ----------------------       ----------------------       ---------------------
                                                   Natural                      Natural                     Natural
                                      Oil           Gas           Oil             Gas           Oil           Gas
                                    --------        ------       -------         ------       -------        -----
                                     (BBLS)         (MMCF)        (BBLS)        (MMCF)        (BBLS)         (MMCF)
<S>                                 <C>             <C>          <C>             <C>          <C>            <C>
Proved developed
   reserves at end of year            12,087           556        16,992            670        20,746           828
                                    ========        ======       =======         ======       =======        ======
Proved reserves

   Balance at beginning
     of year                          18,893           690        23,611            871        36,691           931

   Extensions, discoveries
     and other additions                 147             2            --             --            --            --

   Revisions of previous
     estimates                         1,774            28        (2,140)          (102)         (381)           67

   Sales of minerals in
     place                            (5,309)          (90)          (40)            (4)       (9,548)          (22)

   Production                         (1,517)          (57)       (2,538)           (75)       (3,151)         (105)
                                    --------         -----       -------          -----       -------         -----

   Balance at end of year             13,988           573        18,893            690        23,611           871
                                    ========        ======       =======         ======       =======        ======
</TABLE>

         Revisions  of  previous  quantity  estimates  are  related to upward or
downward  variations  based on current  engineering  information  for production
rates,  volumetrics and reservoir  pressure.  Additionally,  changes in quantity
estimates  are the result of the  increase  or decrease in crude oil and natural
gas prices at each year end which have the effect of adding or  reducing  proved
reserves on marginal properties due to economic limitations.

                                      I-6

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

         The following table summarizes by acquisition the Registrant's reserves
and gross and net  interests in  producing  oil and gas wells as of December 31,
1999:
<TABLE>
<CAPTION>
                                                                 Reserves
                                                             December 31, 1999
                                                       ---------------------------
                                                                           Natural                    Wells
                                                         Oil                 Gas             ------------------------
Acquisition                State(s)                     (BBLS)              (MMCF)            Gross             Net
----------                 ---------                   -------              ------           ------           -------
<S>                        <C>                          <C>                    <C>              <C>             <C>
Potter                     AR, LA, MS,
                           NM, OK, TX                      937                 146              187             5.464
Mega, Northwind            TX                            3,716                  61                7             0.052
Anderson, Samedan
   Oil, Strebor Oil
   & Lake Ronel Oil        TX                              317                 205                6             0.336
Shell Oil Company          TX                            4,378                  94               67             0.281
Union Pacific              AR, KS, NM,
                           OK, TX                        1,881                  14              127             0.490
Allstate                   KS, LA, OK                       60                  22              158             1.328
Norcen Explorer            WY                            1,974                  --               29             0.097
Mission Oil
   Company                 TX                              325                  14               47             0.196
Hardy Oil Company          TX                              400                  17                4             0.008
                                                       -------              ------           ------            ------
                                                        13,988                 573              632             8.252
                                                      ========              ======           ======           =======
</TABLE>

         There are numerous  uncertainties  inherent in estimating quantities of
proved  reserves and in projecting  the future rates of  production,  timing and
plan of  development.  Oil and gas reserve  engineering  must be recognized as a
subjective process of estimating  underground  accumulations of oil and gas that
cannot be measured  in an exact way,  and  estimates  of other  engineers  might
differ  from  those  above,  audited  by H. J.  Gruy and  Associates,  Inc.,  an
independent petroleum consulting firm. The accuracy of any reserve estimate is a
function of the quality of  available  data and of  engineering  and  geological
interpretation  and  judgment.  Results  of  drilling,  testing  and  production
subsequent  to the date of the estimate may justify  revision of such  estimate,
and, as a general rule,  reserve  estimates based upon  volumetric  analysis are
inherently  less  reliable  than  those  based on  lengthy  production  history.
Accordingly,  reserve  estimates are often  different from the quantities of oil
and gas that are ultimately recovered.

         In estimating  the oil and natural gas  reserves,  the  Registrant,  in
accordance with criteria  prescribed by the Securities and Exchange  Commission,
has used prices received as of December 31, 1999 without  escalation,  except in
those instances where fixed and determinable  gas price  escalations are covered
by  contracts,  limited  to the  price the  Partnership  reasonably  expects  to
receive.  The  Registrant  does not believe that any  favorable or adverse event
causing a significant  change in the estimated  quantity of proved  reserves has
occurred between December 31, 1999 and the date of this report.

         Future prices received for the sale of the  Partnership's  products may
be higher or lower than the prices used in the evaluation  described  above; the
operating  costs relating to such  production may also increase or decrease from
existing  levels.  The estimates  presented  above are in accordance  with rules
adopted by the Securities and Exchange Commission.

Item 3. Legal Proceedings

         The Partnership is not aware of any material pending legal  proceedings
to which it is a party or of which any of its property is the subject.

Item 4. Submission of Matters to a Vote of Security Holders

         No matters  were  submitted  to a vote of limited  partners  during the
fourth quarter of the fiscal year covered by this report.

                                      I-7

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

                                     PART II

Item 5. Market Price of and Distributions on the Registrant's  Units and Related
Limited Partner Matters

Market Information

         Units in the  Partnership  were  initially  sold at a price of $100 per
Unit.  Units are not traded on any exchange and there is no  established  public
trading  market for the Units.  Swift is aware of negotiated  transfers of Units
between  unrelated  parties;  however,  these  transfers  have been  limited and
sporadic.  Due to the  nature of these  transactions,  Swift  has no  verifiable
information regarding prices at which Units have been transferred.

Holders

         As of December 31, 1999,  there were 494 Limited Partners holding Units
in the Partnership.

Distributions

         The Partnership  generally makes distributions to Limited Partners on a
quarterly  basis,   subject  to  the  restrictions  set  forth  in  the  Limited
Partnership  Agreement.  In the fiscal years ending  December 31, 1998 and 1999,
the Partnership  distributed a total of $116,300 and $45,900,  respectively,  to
holders of its Units.  Cash  distributions  constitute net proceeds from sale of
oil and gas  production  after  payment of lease  operating  expenses  and other
partnership expenses.  Some or all of such amounts or any proceeds from the sale
of partnership  properties  could be deemed to constitute a return of investors'
capital.

         Oil and gas  investments  involve a high risk of loss, and no assurance
can be given that any particular  level of distributions to holders of Units can
be  achieved  or  maintained.   Although  it  is   anticipated   that  quarterly
distributions  will continue to be made through 2000, the Partnership's  ability
to make distributions  could be diminished by any event adversely  affecting the
oil and gas properties in which the Partnership  owns interests or the amount of
revenues received by the Partnership therefrom.

         The  Partnership's   Limited  Partnership  Agreement  contains  various
provisions  which might serve to delay,  defer or prevent a change in control of
the Partnership,  such as the requirement of a vote of Limited Partners in order
to  sell  all  or  substantially  all  of the  Partnership's  properties  or the
requirement of consent by the Managing  General  Partner to transfers of limited
partnership interests.

                                      II-1

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

Item 6. Selected Financial Data

         The following  selected  financial  data,  prepared in accordance  with
generally  accepted  accounting  principles as of December 31, 1999, 1998, 1997,
1996,  and 1995,  should be read in  conjunction  with the financial  statements
included in Item 8:
<TABLE>
<CAPTION>
                                1999               1998               1997              1996             1995
                           -------------      -------------      --------------    -------------     -------------
<S>                        <C>                <C>                <C>               <C>               <C>
Revenues                   $     154,713      $     170,410      $      329,207    $     407,245     $     383,426
Income (Loss)              $       2,812      $     (99,924)     $       83,141    $      71,156     $    (121,291)
Total Assets               $     543,650      $     606,682      $      852,696    $     947,682     $   1,145,068
Cash Distributions         $      51,116      $     126,551      $      179,976    $      91,609     $      88,406
Long Term Obligations      $          --      $          --      $           --    $          --     $          --
Limited Partners' Net
  Income (Loss) Per Unit   $         .06      $       (1.42)     $         1.50    $        1.25     $       (2.11)
Limited Partners' Cash
  Distributions Per Unit   $         .90      $        2.28      $         3.12    $        1.45     $        1.50
</TABLE>

Item 7. Management's Discussion and Analysis of Financial Condition and
     Results of Operations

Liquidation

         During the first quarter of 2000, the Managing  General  Partner mailed
proxy material to the limited partners  proposing to sell all the  Partnership's
interests in oil and gas properties and dissolve and liquidate the  Partnership.
If this proosal is  approved,  it is  anticipated  that the  liquidation  of the
Partnershi will be substantially completed withing the next two years.

Liquidity and Capital Resources

      Oil and gas reserves are depleting  assets and therefore often  experience
significant  production  declines each year from the date of acquisition through
the end of the life of the  property.  The primary  source of  liquidity  to the
Partnership comes almost entirely from the income generated from the sale of oil
and gas produced from ownership interests in oil and gas properties. This source
of  liquidity  and  the  related  results  of  operations,   and  in  turn  cash
distributions,  will decline in future  periods as the oil and gas produced from
these properties also declines while  production and general and  administrative
costs remain relatively stable making it unlikely that the Partnership will hold
the properties  until they are fully depleted,  but will likely liquidate when a
substantial  majority of the reserves have been produced.  Cash distributions to
partners are determined quarterly,  based upon net proceeds from sale of oil and
gas production after payment of lease operating  expense,  taxes and development
costs, less general and administrative expenses. In addition, future partnership
cash requirements are taken into account to determine necessary cash reserves.

      Net cash provided by operating  activities  totaled  $50,842,  $87,575 and
$187,639 in 1999,  1998 and 1997,  respectively.  Cash provided by property sale
proceeds  totaled  $52,152 and $21,490 in 1999 and 1997,  respectively.  Capital
expenditures  totaled  $5,725,  $11,004  and  $6,241  in 1999,  1998  and  1997,
respectively. Cash distributions totaled $51,116, $126,551 and $179,976 in 1999,
1998 and 1997,  respectively.  In 1999,  cash  distributions  were  effected  by
production declines from the Partnership's  depleting property interests and low
oil and gas prices received during the first part of this year.

      The  Partnership  has  expended  all  of  the  partners'  net  commitments
available for property  acquisitions and development by acquiring  producing oil
and gas  properties.  The  partnership  invests  primarily  in proved  producing
properties  with nominal  levels of future costs of  development  for proven but
undeveloped reserves.  Significant purchases of additional reserves or extensive
drilling  activity  are not  anticipated.  The  Partnership  does not  allow for
additional assessments from the partners to fund capital requirements.  However,
funds in addition to the remaining  unexpended  net capital  commitments  of the
partners are available from  partnership  revenues,  borrowings or proceeds from
the sale of partnership  property.  Subject to 2000 market conditions  remaining
comparable with 1999, the Managing  General  Partner  anticipates an increase in
liquidity provided that certain  development work scheduled in 2000 is completed
successfully. The Partnership plans to spend in the next four years an estimated
$20,000  for  capital  expenditures  needed  for this  development  work and the
enhancement  of  proved  oil and gas  reserves.  The  Managing  General  Partner
believes that the funds currently  available to the Partnership will be adequate
to meet any anticipated capital requirements.

                                      II-2

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

Results of Operations

         Oil and gas sales  declined  $16,517 or 10  percent  in 1999 vs.  1998,
primarily due to decreased oil and gas production.  In 1999,  production volumes
decreased  27  percent as oil and gas  production  declined  40  percent  and 25
percent, respectively,  when compared to 1998. Production declines were a result
of the  accelerated  depletion of the  Partnership's  mature  wells.  Oil prices
increased  57 percent or $6.10/BBL  to an average of  $16.81/BBL  and gas prices
increased 20 percent or $0.36/MCF to an average of $2.13/MCF for 1999. Increased
oil and gas prices helped offset the effect of decreased production.

         Corresponding  production cost per equivalent MCF remained flat in 1999
compared to 1998, and total  production  costs decreased 28 percent in 1999, due
to production declines.

         Total  depreciation  expense for 1999  decreased 68 percent or $100,447
when compared to 1998. In 1998, two components, the normal provision, calculated
on the units of production method, and the additional provision, relating to the
ceiling  limitation,  make up total depreciation  expense.  Normal  depreciation
expense decreased 27 percent or $17,411 in 1999 compared to 1998, related to the
decline in production volumes.

         The  Partnership  records  an  additional  provision  in  depreciation,
depletion and amortization when the present value, discounted at ten percent, of
estimated future net revenues from oil and gas properties,  using the guidelines
of the  Securities  and  Exchange  Commission,  is below the fair  market  value
originally paid for oil and gas properties.  Using prices in effect at March 31,
1999, the Partnership  would have recorded an additional  provision in the first
quarter  of 1999 in the  amount  of  $12,050.  However,  these  temporarily  low
quarter-end  prices  rebounded  and by using prices in effect at the filing date
for  the  first  quarter,  the  Partnership's  unamortized  cost  of oil and gas
properties were not limited by this calculation.

         Oil and gas sales  decreased  48 percent in 1998 vs. 1997. A decline in
the 1998 gas prices received of 28 percent or $.69/MCF had a significant  impact
on partnership performance. The average sales price per equivalent MCF decreased
30 percent in 1998 as gas prices decreased 28 percent and oil prices declined 37
percent.  Also,  production volumes decreased 27 percent due to a 28 percent gas
production  decrease and a 20 percent oil  production  decline.  The decrease in
production,  due in part to  accelerated  production  declines on mature  wells,
further contributed to the decreased revenues.

         Production  cost  per  equivalent  MCF  increased  12  percent  in 1998
compared to 1997,  primarily due to the decline in production volumes;  however,
total production costs decreased 18 percent in 1998.

         Associated  depreciation  expense  decreased  32  percent  in 1998 when
compared to 1997, also related to the decline in production volumes.

         The  Partnership  recorded an  additional  provision  in  depreciation,
depletion and amortization in 1998 of $83,036 when the present value, discounted
at ten percent,  of estimated  future net revenues from oil and gas  properties,
using the guidelines of the Securities  and Exchange  Commission,  was below the
fair  market  value  paid for oil and gas  properties  resulting  in a full cost
ceiling impairment.

         During 2000,  Partnership revenues and costs will be shared between the
limited and general  partners in a 90:10 ratio,  based on the annualized rate of
cash  distributions by the Partnership during a certain period prior to December
31,  1999.  Based on current oil and gas prices,  current  levels of oil and gas
production and expected cash distributions during 2000, the MGP anticipates that
the Partnership sharing ratio will continue to be 90:10.

Year 2000

         The Year 2000  issue  resulted  from  computer  programs  and  embedded
computer  chips with date fields which could not  distinguish  between the years
1900 and 2000. The Managing General Partner  implemented steps necessary to make
its  operations  and  the  related  operations  of the  Partnership  capable  of
addressing the Year 2000. These steps included upgrading, testing and certifying
its  computer  systems and field  operation  services  and  obtaining  Year 2000
compliance  certification  from all important business  suppliers.  The Managing
General  Partner  formed a task force during 1998 to address the Year 2000 issue
and prepare its business systems for the Year 2000. The Managing General Partner
either replaced or updated mission critical systems and completed testing before
2000 began.

                                      II-3

<PAGE>

                   SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

         The Managing  General  Partner's  business  systems are almost entirely
comprised of off-the-shelf  software.  Most of the necessary changes in computer
instructional  code were made by  upgrading  this  software.  In  addition,  the
Managing General Partner received  certification as to Year 2000 compliance from
vendors or third party consultants.

         The costs  incurred to address the Year 2000 issue with  respect to the
Managing  General  Partners'  business systems did not have a material effect on
the  Partnership's  results  of  operations,  or  its  liquidity  and  financial
condition.  The estimated total cost to the Managing  General Partner to address
Year 2000  issues  was less than  $150,000,  most of which was spent  during the
testing phase. The Partnership's share of this cost was insignificant.

         The most  reasonably  likely  worst  case  scenario  would  have been a
prolonged disruption of external power sources upon which core equipment relies,
resulting in a substantial  decrease in the Partnership's oil and gas production
activities.  In addition,  the pipeline  operators to whom the Managing  General
Partner  sells the  Partnership's  natural gas, as well as other  customers  and
suppliers,  could  have  been  prone to Year  2000  problems  that  could not be
assessed or detected by the Managing General Partner.

         As of the filing of this report,  the Managing  General  Partner is not
aware of any Year 2000 problems either  experienced by it or by parties which it
does business, and does not expect to experience such problems in the future.

Item 8. Financial Statements and Supplementary Data

         See Part IV, Item 14(a) for index to financial statements.

Item 9. Disagreements on Accounting and Financial Disclosure

         None.

                                      II-4

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

                                    PART III

Item 10.  Directors and Executive Officers of the Registrant

         As a limited partnership,  the Registrant has no directors or executive
officers.  The  business and affairs of the  Registrant  are managed by Swift as
Managing General Partner. Set forth below is certain information as of March 10,
2000 regarding the directors and executive officers of Swift.
<TABLE>
<CAPTION>
                                                               Position(s) with
         Name                      Age                      Swift and Other Companies
         ----                      ---                      -------------------------
                                              DIRECTORS
                                              ---------
<S>                                <C>                 <C>
A. Earl Swift                      66                  Chief Executive Officer and
                                                       Chairman of the Board

Virgil N. Swift                    71                  Executive Vice President - Business
                                                       Development, Vice Chairman of the Board

G. Robert Evans                    68                  Director of Swift; Chairman of the Board,
                                                       Material Sciences Corporation;
                                                       Director, Consolidated Freightways, Inc.,
                                                       Fibreboard Corporation, Elco Industries, and
                                                       Old Second Bancorp

Raymond O. Loen                    75                  Director of Swift; President, R. O. Loen
                                                       Company

Henry C. Montgomery                64                  Director of Swift; Chairman of the Board,
                                                       Montgomery Financial Services Corporation;
                                                       Director, Southwall Technology Corporation

Clyde W. Smith, Jr.                51                  Director of Swift; President, Somerset
                                                       Properties, Inc.

Harold J. Withrow                  72                  Director of Swift

                                              EXECUTIVE OFFICERS
                                              ------------------

Terry E. Swift                     44                  President

Joe A. D'Amico                     51                  Chief Operating Officer

John R. Alden                      54                  Senior Vice President - Finance,
                                                       Chief Financial Officer and Secretary

Bruce H. Vincent                   52                  Senior Vice President - Funds Management

James M. Kitterman                 55                  Senior Vice President - Operations

Alton D. Heckaman, Jr.             42                  Vice President - Finance and Controller
</TABLE>

                                     III-1

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

         From time to time, Swift as Managing General Partner of the Partnership
purchases Units in the  Partnership  from investors who offer the Units pursuant
to their right of  presentment,  which  purchases are made pursuant to terms set
out in the  Partnership's  original Limited  Partnership  Agreement.  Due to the
frequency  and  large  number  of  these   transactions,   Swift  reports  these
transactions  under  Section  16 of the  Securities  Exchange  Act of 1934 on an
annual  rather than a monthly  basis.  In some cases such annual  reporting  may
constitute a late filing of the required Section 16 reports under the applicable
Section 16 rules.

Item 11.  Executive Compensation

         As  noted  in  Item  10,  "Directors  and  Executive  Officers  of  the
Registrant,"  above,  the Partnership has no executive  officers.  The executive
officers of Swift and VJM are not compensated by the Partnership.

         Certain fees and  allowances  contemplated  by the Limited  Partnership
Agreement  have been paid by the  Partnership  to Swift and VJM. See Note (4) in
Notes  To  Financial   Statements   (Related-Party   Transactions)  for  further
discussion.

Item 12.  Security Ownership of Certain Beneficial Owners and Management

         Swift Energy Company,  the Managing General  Partner,  located at 16825
Northchase  Drive,   Suite  400,  Houston,   Texas  77060,  owns  4,677  Limited
Partnership Units, which is 9.16 percent of all outstanding  Limited Partnership
Units. All Limited Partnership Units owned by Swift were acquired from investors
who  offered  the  Limited   Partnership   Units  pursuant  to  their  right  of
presentment.  As the Managing General Partner, Swift is not permitted generally,
under the Limited Partnership Agreement,  to vote its Limited Partnership Units.
Swift also owns a general  partnership  interest of 9 percent of all partnership
interests in the Partnership.

         Swift and VJM are not aware of any arrangement,  the operation of which
may at a subsequent date result in a change in control of the Partnership.

Item 13.  Certain Relationships and Related Transactions

         As  noted  in  Item  10,  "Directors  and  Executive  Officers  of  the
Registrant," above, the Partnership has no executive officers or directors,  and
thus has not  engaged  in any  transactions  in which  any  such  person  had an
interest.  The Partnership is permitted to engage in certain  transactions  with
Swift as Managing General Partner and VJM as Special General Partner, subject to
extensive  guidelines  and  restrictions  as  described  in  the  "Conflicts  of
Interest"  section  of the  Amended  Prospectus  contained  in the  Registration
Statement, which is incorporated herein by reference.

         Summarized  below are the  principal  transactions  that have  occurred
between the Partnership and Swift, VJM and their affiliates.

         1. The oil and gas properties acquired by the Partnership, as described
in Item 2, "Properties"  above, were typically  acquired initially by Swift from
the  seller  thereof  and  subsequently  transferred  to the  Partnership.  Such
transfers  were made by Swift at its Property  Acquisition  Costs (as defined in
the  Limited  Partnership  Agreement),  less any amounts  received  from sale of
production  between the time of acquisition by Swift and the time of sale to the
Partnership.

         2. Swift  acts  as  operator  for  many  of  the  wells  in  which  the
Partnership  has  acquired  interests  and has  received  compensation  for such
activities in accordance with standard industry operating agreements.

         3. The  Partnership  paid to Swift and VJM certain fees as contemplated
by the  Limited  Partnership  Agreement.  See Note  (4) in  Notes  To  Financial
Statements (Related-Party Transactions) for further discussion.

                                     III-2

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

                                     PART IV

Item 14.  Exhibits, Financial Statement Schedules and Reports on Form 8-K
<TABLE>
<CAPTION>
      <S>      <C>                                                        <C>
      a(1)     FINANCIAL STATEMENTS                                       PAGE NO.
               --------------------                                       --------

               Report of Independent Public Accountants                     IV-2

               Balance Sheets as of December 31, 1999 and 1998              IV-3

               Statements of Operations for the years ended
                  December 31, 1999, 1998 and 1997                          IV-4

               Statements of Partners' Capital for the years ended
                  December 31, 1999, 1998 and 1997                          IV-5

               Statements of Cash Flows for the years ended
                  December 31, 1999, 1998 and 1997                          IV-6

               Notes to Financial Statements                                IV-7
</TABLE>

       a(2)    FINANCIAL STATEMENT SCHEDULES

               All schedules required by the SEC are either  inapplicable or the
               required information is included in the Financial Statements, the
               Notes thereto, or in other information included elsewhere in this
               report.

       a(3)    EXHIBITS

               3.1    Limited  Partnership  Agreement  of  Swift  Energy  Income
                      Partners  1988-C,  Ltd.,  dated September 30, 1988.  (Form
                      10-K for year ended December 31, 1988, Exhibit 3.1).

               3.2    Certificate of Limited  Partnership of Swift Energy Income
                      Partners 1988-C,  Ltd., as filed October 3, 1988, with the
                      Texas  Secretary  of  State.  (Form  10-K for  year  ended
                      December 31, 1988, Exhibit 3.2).

               10.1   Net  Profits and  Overriding  Royalty  Interest  Agreement
                      between  Swift Energy  Income  Partners  1988-C,  Ltd. and
                      Swift Energy Managed  Pension Assets  Partnership  1988-B,
                      Ltd. dated October 18, 1988. (Form 10-K for the year ended
                      December 31, 1988, Exhibit 10.1).

               99.1   A copy of the following section of the Amended  Prospectus
                      dated  March  28,  1988,   contained   in   Post-Effective
                      Amendment No. 1 to Registration  Statement No. 33-11773 on
                      Form S-1 for Swift Energy Income Partners III, as filed on
                      March 25,  1988,  which have been  incorporated  herein by
                      reference:   "Proposed   Activities"  (pp  36  -  50)  and
                      "Conflicts of Interest" (pp. 70 - 78). (Form 10-K for year
                      ended December 31, 1989, Exhibit 28.1).

       b(1)    REPORTS ON FORM 8-K

         No  reports  on Form 8-K have  been  filed  during  the  quarter  ended
December 31, 1999.

Supplemental  Information to be Furnished with Reports Filed Pursuant to Section
15(d) of the Act by Registrants Which Have Not Registered Securities Pursuant to
Section 12 of the Act.

         No annual report to security  holders covering the  Partnership's  1999
fiscal  year  has been sent to Limited Partners of the Partnership.

                                      IV-1

<PAGE>

                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS

To Swift Energy Income Partners 1988-C, Ltd.:

         We have audited the accompanying  balance sheets of Swift Energy Income
Partners 1988-C, Ltd., (a Texas limited partnership) as of December 31, 1999 and
1998, and the related statements of operations, partners' capital and cash flows
for the years ended December 31, 1999, 1998 and 1997. These financial statements
are  the  responsibility  of the  Managing  General  Partner's  management.  Our
responsibility  is to express an opinion on these financial  statements based on
our audits.

         We conducted our audits in accordance with auditing standards generally
accepted in the United States.  Those standards require that we plan and perform
the audit to obtain reasonable  assurance about whether the financial statements
are free of material misstatement. An audit includes examining, on a test basis,
evidence supporting the amounts and disclosures in the financial statements.  An
audit also includes  assessing the accounting  principles  used and  significant
estimates  made by  management,  as well as  evaluating  the  overall  financial
statement  presentation.  We believe that our audits provide a reasonable  basis
for our opinion.

         In our opinion,  the  financial  statements  referred to above  present
fairly, in all material respects,  the financial position of Swift Energy Income
Partners 1988-C,  Ltd., as of December 31, 1999 and 1998, and the results of its
operations  and its cash flows for the years ended  December 31, 1999,  1998 and
1997, in conformity with accounting  principles generally accepted in the United
States.

                                                       ARTHUR ANDERSEN LLP




Houston, Texas
February 9, 2000

                                      IV-2

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                                 BALANCE SHEETS
                           DECEMBER 31, 1999 AND 1998


<TABLE>
<CAPTION>
                                                                         1999                  1998
                                                                   ----------------      ----------------
<S>                                                                <C>                   <C>
    ASSETS:

    Current Assets:
        Cash and cash equivalents                                  $         62,311      $         16,158
        Oil and gas sales receivable                                         24,024                36,622
                                                                   ----------------      ----------------
             Total Current Assets                                            86,335                52,780
                                                                   ----------------      ---------------

    Gas Imbalance Receivable                                                  6,075                 8,832
                                                                   ----------------      -----------------

    Oil and Gas Properties, using full cost
        accounting                                                        4,788,421             4,834,848
    Less-Accumulated depreciation, depletion
        and amortization                                                 (4,337,181)           (4,289,778)
                                                                   ----------------      ----------------
                                                                            451,240               545,070
                                                                   ----------------      ----------------
                                                                   $        543,650      $        606,682
                                                                   ================      ================


    LIABILITIES AND PARTNERS' CAPITAL:

    Current Liabilities:
        Accounts Payable                                           $          8,078      $         19,868
                                                                   ----------------      ----------------

    Deferred Revenues                                                        22,108                25,046

    Limited Partners' Capital (51,090.57 Limited Partnership
                                Units; $100 per unit)                       503,331               548,778

    General Partners' Capital                                                10,133                12,990
                                                                   ----------------      ----------------
             Total Partners' Capital                                        513,464               561,768
                                                                   ----------------      ----------------
                                                                   $        543,650      $        606,682
                                                                   ================      ================
</TABLE>



                 See accompanying notes to financial statements.

                                      IV-3

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                            STATEMENTS OF OPERATIONS
              FOR THE YEARS ENDED DECEMBER 31, 1999, 1998 AND 1997

<TABLE>
<CAPTION>
                                                                       1999               1998               1997
                                                                  ---------------    ---------------    ---------------
     <S>                                                          <C>                <C>                <C>
     REVENUES:

          Oil and gas sales                                       $       152,278    $       168,795   $        326,285
          Interest income                                                   2,435              1,067              2,131
          Other                                                                --                548                791
                                                                  ---------------    ---------------    ---------------
                                                                          154,713            170,410            329,207
                                                                  ---------------    ---------------    ---------------


     COSTS AND EXPENSES:

          Lease operating                                                  45,030             64,576             70,032
          Production taxes                                                  8,977              9,983             20,427
          Depreciation, depletion
               and amortization -
                  Normal                                                   47,403             64,814             95,921
                  Additional                                                   --             83,036                 --
          General and administrative                                       50,491             47,925             59,686
                                                                  ---------------    ---------------    ---------------
                                                                          151,901            270,334            246,066
                                                                  ---------------    ---------------    ---------------
     NET INCOME (LOSS)                                            $         2,812    $       (99,924)   $        83,141
                                                                  ===============    ===============    ===============
</TABLE>






                 See accompanying notes to financial statements.

                                      IV-4

<PAGE>



                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                         STATEMENTS OF PARTNERS' CAPITAL
              FOR THE YEARS ENDED DECEMBER 31, 1999, 1998 AND 1997


<TABLE>
<CAPTION>
                                                Limited            General          Combining
                                                Partners           Partners         Adjustment            Total
                                             -------------     --------------     --------------     --------------
<S>                                          <C>               <C>                <C>                <C>
Balance,
     December 31, 1996                       $     793,212     $       28,018     $       63,848     $      885,078

Income (Loss)                                       76,390             13,748            (6,997)             83,141

Cash Distributions                                (159,600)           (20,376)                --           (179,976)
                                             -------------     --------------     --------------     --------------

Balance,
     December 31, 1997                             710,002             21,390             56,851            788,243
                                             -------------     --------------     --------------     --------------

Income (Loss)                                      (72,765)             1,851            (29,010)           (99,924)

Cash Distributions                                (116,300)           (10,251)                --           (126,551)
                                             -------------     --------------     --------------     --------------

Balance,
     December 31, 1998                             520,937             12,990             27,841            561,768
                                             --- ---------     --------------     --------------     --------------

Income (Loss)                                        2,974              2,359             (2,521)             2,812

Cash Distributions                                 (45,900)            (5,216)                --            (51,116)
                                             -------------     --------------     --------------     --------------

Balance,
     December 31, 1999                       $     478,011     $       10,133     $       25,320    $       513,464
                                             =============     ==============     ==============     ==============



Limited Partners' net income (loss)
     per unit

     1997                                    $        1.50
                                             =============

     1998                                    $       (1.42)
                                             =============

     1999                                    $        0.06
                                             =============
</TABLE>

                 See accompanying notes to financial statements.

                                      IV-5

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                            STATEMENTS OF CASH FLOWS
              FOR THE YEARS ENDED DECEMBER 31, 1999, 1998 AND 1997


<TABLE>
<CAPTION>
                                                                            1999              1998             1997
                                                                        ------------     -------------    --------------
<S>                                                                     <C>              <C>              <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
     Income (loss)                                                      $      2,812     $     (99,924)   $       83,141
     Adjustments to reconcile income (loss) to
          net cash provided by operations:
          Depreciation, depletion and amortization                            47,403           147,850            95,921
          Change in gas imbalance receivable
               and deferred revenues                                            (181)             (162)            5,725
          Change in assets and liabilities:
               (Increase) decrease in oil and gas sales receivable            12,598            57,343             1,899
               Increase (decrease) in accounts payable                       (11,790)          (17,532)              953
                                                                        ------------     -------------    --------------
          Net cash provided by (used in) operating activities                 50,842            87,575           187,639
                                                                        ------------     -------------    --------------

CASH FLOWS FROM INVESTING ACTIVITIES:
     Additions to oil and gas properties                                      (5,725)          (11,004)           (6,241)
     Proceeds from sales of oil and gas properties                            52,152                --            21,490
                                                                        ------------     -------------    --------------
          Net cash provided by (used in) investing activities                 46,427           (11,004)           15,249
                                                                        ------------     -------------    --------------

CASH FLOWS FROM FINANCING ACTIVITIES:
     Cash distributions to partners                                          (51,116)         (126,551)         (179,976)
                                                                        ------------     -------------    --------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                          46,153           (49,980)           22,912
                                                                        ------------     -------------    --------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR                                16,158            66,138            43,226
                                                                        -------------    -------------    --------------
CASH AND CASH EQUIVALENTS AT END OF YEAR                                $     62,311     $      16,158    $       66,138
                                                                        ============     =============    ==============
</TABLE>





                 See accompanying notes to financial statements.

                                      IV-6

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                          NOTES TO FINANCIAL STATEMENTS

(1) Organization and Terms of Partnership Agreement -

         Swift Energy Income Partners 1988-C,  Ltd., a Texas limited partnership
("the  Partnership"),  was  formed  on  October  3,  1988,  for the  purpose  of
purchasing and operating producing oil and gas properties within the continental
United States.  Swift Energy Company  ("Swift"),  a Texas  corporation,  and VJM
Corporation ("VJM"), a California corporation, serve as Managing General Partner
and  Special  General  Partner of the  Partnership,  respectively.  The  general
partners  are  required  to  contribute  up to 1/99th  of  limited  partner  net
contributions.  The 535 limited  partners  made total capital  contributions  of
$5,109,057.

         Property  acquisition costs and the management fee are borne 99 percent
by the limited  partners and one percent by the general  partners.  Organization
and syndication costs were borne solely by the limited partners.

         Initially, all continuing costs (including development costs, operating
costs,  general  and  administrative  reimbursements  and direct  expenses)  and
revenues are allocated 90 percent to the limited partners and ten percent to the
general partners. If prior to partnership payout, as defined,  however, the cash
distribution rate for a certain period equals or exceeds 17.5 percent,  then for
the  following  calendar  year,  these  continuing  costs and  revenues  will be
allocated  85  percent to the  limited  partners  and 15 percent to the  general
partners. After partnership payout, continuing costs and revenues will be shared
85 percent by the limited partners, and 15 percent by the general partners, even
if the cash distribution rate is less than 17.5 percent. Payout had not occurred
as of December 31, 1999.

         During the first quarter of 2000, the Managing  General  Partner mailed
proxy material to the limited partners  proposing to sell all the  Partnership's
interests in oil and gas properties and dissolve and liquidate the  Partnership.
If this proposal is approved,  it is  anticipated  that the  liquidation  of the
Partnership will be substantially completed within the next two years.

(2) Significant Accounting Policies -

Use of Estimates --

         The  preparation of financial  statements in conformity  with generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions  that affect the reported  amounts of assets and  liabilities at the
date of the  financial  statements  and the  reported  amounts of  revenues  and
expenses  during  the  reporting  period.   Actual  results  could  differ  from
estimates.

Oil and Gas Revenues --

         Oil and gas revenues are reported using the entitlement method in which
the  Partnership  recognizes  its interest in oil and natural gas  production as
revenue.

Oil and Gas Properties --

         The  Partnership  accounts  for its  ownership  interest in oil and gas
properties   using  the   proportionate   consolidation   method,   whereby  the
Partnership's share of assets, liabilities, revenues and expenses is included in
the appropriate classification in the financial statements.

         For  financial   reporting   purposes,   the  Partnership  follows  the
"full-cost"  method of  accounting  for oil and gas property  costs.  Under this
method of accounting,  all productive  and  nonproductive  costs incurred in the
acquisition and development of oil and gas reserves are capitalized.  Such costs
include lease  acquisitions,  geological  and  geophysical  services,  drilling,
completion,  equipment and certain  general and  administrative  costs  directly
associated   with   acquisition   and   development   activities.   General  and
administrative  costs related to production and general overhead are expensed as
incurred.  No general and administrative costs were capitalized during the years
ended December 31, 1999, 1998 and 1997.

         Future  development,  site  restoration,  dismantlement and abandonment
costs,  net of salvage  values,  are estimated on a  property-by-property  basis
based on  current  economic  conditions  and are  amortized  to  expense  as the
Partnership's capitalized oil and gas property costs are amortized.

                                      IV-7

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                    NOTES TO FINANCIAL STATEMENTS (CONTINUED)

         The  unamortized  cost of oil  and gas  properties  is  limited  to the
"ceiling  limitation",  (calculated  separately  for  the  Partnership,  limited
partners,  and general  partners).  The "ceiling  limitation" is calculated on a
quarterly  basis and  represents  the estimated  future net revenues from proved
properties  using current prices,  discounted at ten percent.  Proceeds from the
sale or  disposition of oil and gas properties are treated as a reduction of oil
and gas  property  costs  with no gains or  losses  being  recognized  except in
significant transactions.

         The Partnership computes the provision for depreciation,  depletion and
amortization of oil and gas properties on the units-of-production  method. Under
this method,  the provision is calculated by multiplying  the total  unamortized
cost of oil and gas properties,  including future development, site restoration,
dismantlement  and abandonment  costs, by an overall  amortization  rate that is
determined  by dividing  the physical  units of oil and gas produced  during the
period  by the  total  estimated  units of proved  oil and gas  reserves  at the
beginning of the period.

         The  calculation  of the "ceiling  limitation"  and the  provision  for
depreciation,  depletion,  and  amortization  is based on  estimates  of  proved
reserves.  There are numerous uncertainties inherent in estimating quantities of
proved  reserves and in projecting  the future rates of  production,  timing and
plan of development.  The accuracy of any reserve  estimate is a function of the
quality of available data and of engineering and geological  interpretation  and
judgment.  Results of drilling, testing and production subsequent to the date of
the  estimate  may  justify  revision  of such  estimate.  Accordingly,  reserve
estimates  are  often  different  from  the  quantities  of oil and gas that are
ultimately recovered.

Cash and Cash Equivalents --

         Highly liquid debt instruments with an initial maturity of three months
or less are considered to be cash equivalents.

Reclassifications --

         Certain  reclassifications have been made to the prior year balances to
conform with the current year presentation.

(3) Oil and Gas Capitalized Costs -

         The  following  table sets forth  capital  expenditures  related to the
Partnership's oil and gas operations:
<TABLE>
<CAPTION>
                                         Year Ended December 31,
                                ----------------------------------------
                                 1999              1998           1997
                                ------           -------       ---------
<S>                             <C>              <C>           <C>
Acquisition of
  proved properties             $   --           $    --       $      --

Development                      5,725            11,004           6,241
                                ------           --------      ---------
                                $5,725           $11,004       $   6,241
                                ======           =======       =========
</TABLE>

         All oil and gas  property  acquisitions  are made by Swift on behalf of
the Partnership. The costs of the properties include the purchase price plus any
costs incurred by Swift in the evaluation and acquisition of properties.

                                      IV-8

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                    NOTES TO FINANCIAL STATEMENTS (CONTINUED)

         During 1998, the  Partnership's  unamortized oil and gas property costs
exceeded the quarterly  calculations of the "ceiling limitation" resulting in an
additional provision for depreciation, depletion and amortization of $83,036. In
addition,  the limited partners' share of unamortized oil and gas property costs
exceeded their "ceiling  limitation" in 1998 resulting in a valuation  allowance
of $59,108.  This amount is included in the income  (loss)  attributable  to the
limited  partners shown in the statements of partners'  capital  together with a
"combining  adjustment"  for  the  differences  between  the  limited  partners'
valuation  allowances  and the  Partnership's  full cost ceiling write down. The
"combining   adjustment"   changes   quarterly   as  the   Partnership's   total
depreciation,  depletion  and  amortization  provision  is more or less than the
combined depreciation,  depletion and amortization provision attributable to the
general and limited partners.

(4) Related-Party Transactions -

         An  affiliate  of the  Special  General  Partner,  as  Dealer  Manager,
received   $127,726  for  managing  and   overseeing  the  offering  of  limited
partnership units.

         A one-time  management  fee of  $127,726  was paid to Swift in 1988 for
services  performed  for the  Partnership.  During  1999,  1998  and  1997,  the
Partnership   paid  Swift  $26,138,   $30,729  and  $37,673  as  a  general  and
administrative overhead allowance.

         Effective October 18, 1988, the Partnership  entered into a Net Profits
and Overriding Royalty Interests Agreement ("NP/OR Agreement") with Swift Energy
Managed Pension Assets Partnership 1988-B, Ltd. ("Pension Partnership"), managed
by Swift,  for the purpose of acquiring  working  interests in producing oil and
gas properties. Under terms of the NP/OR Agreement, the Partnership has conveyed
to the Pension Partnership a nonoperating  interest in the aggregate net profits
(i.e.,  oil and gas  sales net of  related  operating  costs) of the  properties
acquired equal to its proportionate share of the property acquisition costs.

(5) Federal Income Taxes -

         The Partnership is not a tax-paying entity. No provision is made in the
accounts of the Partnership for federal or state income taxes,  since such taxes
are liabilities of the individual partners,  and the amounts thereof depend upon
their respective tax situations.

         The tax returns and the amount of distributable  Partnership income are
subject to  examination  by the federal  and state  taxing  authorities.  If the
Partnership's  ordinary  income for federal  income tax  purposes is  ultimately
changed by the taxing  authorities,  the tax  liability of the limited  partners
could be changed  accordingly.  Ordinary  income  reported on the  Partnership's
federal  return of income for the years ended  December 31, 1999,  1998 and 1997
was $69,248, $42,803 and $161,316, respectively. The difference between ordinary
income for  federal  income tax  purposes  reported by the  Partnership  and net
income or loss reported herein primarily results from the exclusion of depletion
(as described below) from ordinary income reported in the Partnership's  federal
return of income.

         For federal  income tax purposes,  depletion with respect to production
of  oil  and  gas  is  computed  separately  by  the  partners  and  not  by the
Partnership.  Since the amount of depletion on the  production of oil and gas is
not  computed  at  the  Partnership  level,  depletion  is not  included  in the
Partnership's  income for federal income tax purposes but is charged directly to
the  partners'  capital  accounts  to the  extent  of the cost of the  leasehold
interests, and thus is treated as a separate item on the partners' Schedule K-1.
Depletion  for  federal  income tax  purposes  may vary from that  computed  for
financial reporting purposes in cases where a ceiling adjustment is recorded, as
such amount is not recognized for tax purposes.

(6) Gas Imbalances -

         The  Partnership  recognizes  its  ownership  interest  in natural  gas
production as revenue.  Actual production  quantities sold may be different than
the Partnership's  ownership share in a given period. If the Partnership's sales
exceed its  ownership  share of  production,  the  differences  are  recorded as
deferred revenue. Gas balancing  receivables are recorded when the Partnership's
ownership share of production exceeds sales.

                                     IV-9

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.
                    NOTES TO FINANCIAL STATEMENTS (CONTINUED)

(7) Vulnerability Due to Certain Concentrations -

         The Partnership's revenues are primarily the result of sales of its oil
and natural gas  production.  Market prices of oil and natural gas may fluctuate
and adversely affect operating results.

         In the normal  course of  business,  the  Partnership  extends  credit,
primarily  in the form of  monthly  oil and gas sales  receivables,  to  various
companies in the oil and gas industry which results in a concentration of credit
risk. This  concentration  of credit risk may be affected by changes in economic
or other conditions and may accordingly impact the Partnership's  overall credit
risk. However,  the Managing General Partner believes that the risk is mitigated
by the size,  reputation,  and nature of the companies to which the  Partnership
extends  credit.  In  addition,  the  Partnership  generally  does  not  require
collateral or other security to support customer receivables.

(8) Fair Value of Financial Instruments -

         The  Partnership's  financial  instruments  consist  of cash  and  cash
equivalents  and  short-term  receivables  and  payables.  The carrying  amounts
approximate  fair  value  due to the  highly  liquid  nature  of the  short-term
instruments.

                                     IV-10

<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.


                                   SIGNATURES

Pursuant to the  requirements of Section 13 or 15(d) of the Securities  Exchange
Act of 1934,  the  Registrant  has duly  caused  this report to be signed on its
behalf by the undersigned thereunto duly authorized.

                                            SWIFT ENERGY INCOME
                                            PARTNERS 1988-C, LTD.
                                            (Registrant)

                                   By:      SWIFT ENERGY COMPANY
                                             General Partner

Date:      March 10, 2000          By:      s/b A. Earl Swift
         ----------------                   -------------------------------
                                            A. Earl Swift
                                            Chief Executive Officer

Date:      March 10, 2000          By:      s/b John R. Alden
         ----------------                  -------------------------------
                                            John R. Alden
                                            Principal Financial Officer

Date:      March 10, 2000          By:      s/b Alton D. Heckaman, Jr.
         ----------------                   -------------------------------
                                            Alton D. Heckaman, Jr.
                                            Principal Accounting Officer

Pursuant to the requirements of the Securities Exchange Act of 1934, this report
has been signed below by the following  persons on behalf of the  Registrant and
in the capacities and on the dates indicated.

                                            SWIFT ENERGY INCOME
                                            PARTNERS 1988-C, LTD.
                                            (Registrant)

                                   By:      SWIFT ENERGY COMPANY
                                             General Partner

Date:      March 10, 2000          By:      s/b A. Earl Swift
         -----------------                  -------------------------------
                                            A. Earl Swift
                                            Director and Principal
                                            Executive Officer

Date:      March 10, 2000          By:      s/b Virgil N. Swift
         -----------------                  -------------------------------
                                            Virgil N. Swift
                                            Director and Executive
                                            Vice President - Business
                                            Development


                                      V-1
<PAGE>

                    SWIFT ENERGY INCOME PARTNERS 1988-C, LTD.

                                   SIGNATURES



Date:      March 10, 2000          By:      s/b G. Robert Evans
         -----------------                  -------------------------------
                                            G. Robert Evans
                                            Director

Date:      March 10, 2000          By:      s/b Raymond O. Loen
         -----------------                  -------------------------------
                                            Raymond O. Loen
                                            Director

Date:      March 10, 2000          By:      s/b Henry C. Montgomery
         -----------------                  -------------------------------
                                            Henry C. Montgomery
                                            Director

Date:      March 10, 2000          By:      s/b Clyde W. Smith, Jr.
         -----------------                  -------------------------------
                                            Clyde W. Smith, Jr.
                                            Director

Date:      March 10, 2000          By:      s/b Harold J. Withrow
         -----------------                  -------------------------------
                                            Harold J. Withrow
                                            Director

                                       V-2