<PAGE>



                                                                   EXHIBIT 10.10

            FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT

         THIS FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT
(hereinafter referred to as the "First Amendment") executed as of the 17th of
December, 2002, by and among ATWOOD OCEANICS, INC., a Texas corporation
("Atwood"), ATWOOD DEEP SEAS, LTD., a Texas limited partnership ("Deep Seas")
(Atwood and Deep Seas shall hereinafter be collectively referred to as
"Borrowers", and individually, "Borrower") and BANK ONE, NA, a national banking
association ("Bank One"), and each of the financial institutions which is a
party hereto (as evidenced by the signature pages to this Agreement) or which
may from time to time become a party hereto pursuant to the provisions of
Section 27 of the Credit Agreement or any successor or assignee thereof
(hereinafter collectively referred to as "Banks", and individually, "Bank") and
Bank One, as Administrative and Documentation Agent (the "Agent") and NORDEA, as
Documentation Agent and Credit Lyonnais, New York Branch, and Fortis Capital
Corp., as Syndication Agents.

                                   WITNESSETH:

         WHEREAS, as of February 20, 2002, Borrowers, the Banks and the Agent
entered into an Amended and Restated Credit Agreement pursuant to which the
Banks made available to the Borrowers a revolving credit facility of up to
$75,000,000 (the "Credit Agreement"); and

         WHEREAS, the Borrowers have requested that the Banks agree to make
certain amendments to the Credit Agreement and the Banks have agreed to do so on
the terms and conditions hereinafter set forth.

         NOW, THEREFORE, the parties agree to amend the Credit Agreement as
follows:

         1. Unless otherwise defined herein all defined terms used herein shall
have the same meaning as ascribed to such terms in the Credit Agreement.

         2. Section 1 of the Credit Agreement is hereby amended in the following
respects:

                  (a) By deletion of the definition of "Base Rate Margin" and
         substitution of the following in lieu thereof:

                           "Base Rate Margin shall mean:

                                    (i) two percent (2%) per annum whenever
                           Atwood's ratio of Consolidated Funded Debt to
                           Consolidated EBITDA is equal to or greater than 4.0
                           to 1.0; or

                                    (ii) one and one-half percent (1.50%) per
                           annum whenever Atwood's ratio of Consolidated Funded
                           Debt to

<PAGE>

                           Consolidated EBITDA is less than 4.0 to 1.0 but equal
                           to or greater than 3.25 to 1.0; or

                                    (iii) one percent (1%) per annum whenever
                           Atwood's ratio of Consolidated Funded Debt to
                           Consolidated EBITDA is less than 3.25 to 1.0 but
                           equal to or greater than 2.75 to 1.0; or

                                    (iv) three-fourths of one percent (.75%) per
                           annum whenever Atwood's ratio of Consolidated Funded
                           Debt to Consolidated EBITDA is less than 2.75 to 1.0
                           but equal to or greater than 2.25 to 1.0; or

                                    (v) one-half of one percent (.50%) per annum
                           whenever Atwood's ratio of Consolidated Funded Debt
                           to Consolidated EBITDA is less than 2.25 to 1.0 but
                           equal to or greater than 1.75 to 1.0; or

                                    (vi) one-quarter of one percent (.25%) per
                           annum whenever Atwood's ratio of Consolidated Funded
                           Debt to Consolidated EBITDA is less than 1.75 to 1.0.

                  The Base Rate Margin shall be calculated by Agent quarterly
                  upon the earlier of (i) receipt by Agent of Borrowers'
                  Certificates of Compliance required pursuant to Section 11(b)
                  hereof or (ii) the occurrence of any Event of Default. The
                  Base Rate Margin shall be two percent (2%) per annum as of the
                  First Amendment Effective Date and shall remain at such rate
                  until receipt by the Agent of the next quarterly Certificate
                  of Compliance.

                  (b) By deletion of the definition of "LIBOR Margin" and
         substitution of the following in lieu thereof:

                           "LIBOR Margin" shall be:

                                    (i) three and one-half percent (3.50%) per
                           annum whenever Atwood's ratio of Consolidated Funded
                           Debt to Consolidated EBITDA is equal to or greater
                           than 4.0 to 1.0; or

                                    (ii) three percent (3%) per annum whenever
                           Atwood's ratio of Consolidated Funded Debt to
                           Consolidated EBITDA is less than 4.0 to 1.0 but equal
                           to or greater than 3.25 to 1.0; or

                                    (iii) two and one-half percent (2.5%) per
                           annum whenever Atwood's ratio of Consolidated Funded
                           Debt to


                                      -2-
<PAGE>

                           Consolidated EBITDA is less than 3.25 to 1.0 but
                           equal to or greater than 2.75 to 1.0; or

                                    (iv) two and one-quarter percent (2.25%) per
                           annum whenever Atwood's ratio of Consolidated Funded
                           Debt to Consolidated EBITDA is less than 2.75 to 1.0
                           but equal to or greater than 2.25 to 1.0; or

                                    (v) two percent (2%) per annum whenever
                           Atwood's ratio of Consolidated Funded Debt to
                           Consolidated EBITDA is less than 2.25 to 1.0 but
                           equal to or greater than 1.75 to 1.0; or

                                    (vi) one and three-quarters percent (1.75%)
                           per annum whenever Atwood's ratio of Consolidated
                           Funded Debt to Consolidated EBITDA is less than 1.75
                           to 1.0.

                  The LIBOR Margin shall be calculated by Agent quarterly upon
                  the earlier of (i) receipt by Agent of Borrowers' Certificate
                  of Compliance required pursuant to Section 11(b) hereof or
                  (ii) the occurrence of any Event of Default. The LIBOR Margin
                  shall be three and one-half percent (3.50%) per annum as of
                  the First Amendment Effective Date and shall remain at such
                  rate until receipt by the Agent of the next quarterly
                  Certificate of Compliance.

                  (c) By the deletion of the definition of "Unused Commitment
         Fee Rate" and substitution of the following in lieu thereof:

                           "Unused Commitment Fee Rate" shall be:

                                    (i) one-half of one percent (.50%) per annum
                           whenever Atwood's ratio of Consolidated Funded Debt
                           to Consolidated EBITDA is greater than 3.25 to 1.0;
                           or

                                    (ii) three-eighths of one percent (.375%)
                           per annum whenever Atwood's ratio of Consolidated
                           Funded Debt to Consolidated EBITDA is equal to or
                           less than 3.25 to 1.0.

                  The Unused Commitment Fee shall be calculated by Agent
                  quarterly upon the earlier of (i) receipt by Agent of
                  Borrowers' Certificate of Compliance provided pursuant to
                  Section 11(b) hereof or (ii) the occurrence of any Event of
                  Default. The Unused Commitment Fee shall be one-half of one
                  percent (.50%) per annum as of the First Amendment Effective
                  Date and shall remain at such rate until receipt by the Agent
                  of the next quarterly Certificate of Compliance.


                                      -3-
<PAGE>

         3. Section 6 of the Credit Agreement is hereby amended in the following
respects:

                  (a) By the deletion of any and all references in Section 6 to
         "Guarantors".

                  (b) By the deletion of the last unnumbered paragraph thereof
         and substituting the following in lieu thereof:

                           "In addition to the foregoing, Borrowers shall also
                  grant to the Banks a pledge on all of their accounts
                  receivable, contracts, rights, intangibles, inventory and
                  other assets. In addition, Borrowers shall also grant to Banks
                  a negative pledge on all of their assets which are not
                  directly mortgaged or pledged to the Banks (limited, in the
                  case of the voting stock of foreign subsidiaries, to 66% of
                  such stock."

         4. Section 11 of the Credit Agreement is hereby amended in the
following respects:

                  (a) Subsection 11(a)(v) of the Credit Agreement is hereby
         deleted and the following inserted in lieu thereof:

                           "(v) Fleet Employment Report. As soon as available,
                  and in any event within twenty-one (21) days after the end of
                  each month, the monthly fleet employment report of Borrowers
                  setting forth the location, charter, term, and rate for all
                  offshore drilling rigs owned or managed by Borrowers or their
                  Subsidiaries as of the date of such report, such reports to be
                  in form and substance satisfactory to Agent; and"

                  (b) Subsection 11(e) of the Credit Agreement is hereby deleted
         in its entirety and the following substituted in lieu thereof:

                           "(e) Annual Appraisals. Provide with each Certificate
                  of Compliance required to be furnished for the fiscal quarter
                  ended each June 30th pursuant to Section 11(b) hereof, an
                  annual desktop appraisal of the Rigs prepared by an
                  independent appraisal firm or offshore drilling brokerage firm
                  chosen by the Agent and reasonably acceptable to the
                  Borrowers."

                  (c) Subsection 11(q) of the Credit Agreement is amended by the
         addition of the following new sentence at the end thereof:

                           "In addition to the foregoing, the Borrowers hereby
                  agree at the request of Agent based upon Agent's review of the
                  then current financial condition and contract status of Atwood
                  and its Subsidiaries, to mortgage or cause to be mortgaged,
                  the ATWOOD BEACON to the Banks within thirty (30) days after
                  receipt of delivery of the said ATWOOD BEACON by Borrowers or
                  any of their Subsidiaries from the shipyard."


                                      -4-
<PAGE>

         5. Section 12 of the Credit Agreement is hereby amended in the
following respects:

                  (a) Subsection 12(c) of the Credit Agreement is hereby deleted
         in its entirety and the following inserted in lieu thereof:

                           "(c) Funded Debt to EBITDA. The Borrowers will not
                  allow their ratio of (i) Consolidated Funded Debt to (ii)
                  Consolidated EBITDA to be greater than (A) 5.0 to 1.0 as of
                  the end of any fiscal quarter from December 31, 2002, (B) 4.75
                  to 1.0 as of March 31, 2003, (C) 4.25 to 1.0 as of June 30,
                  2003, and (D) 2.75 to 1.0 as of September 30, 2003 and as of
                  the end of each fiscal quarter thereafter."

                  (b) Subsection 12(i) of the Credit Agreement is hereby deleted
         in its entirety and the following inserted in lieu thereof:

                           "(i) Dividends. Borrowers will not declare or pay any
                  cash dividend, purchase, redeem or otherwise acquire for value
                  any of their stock now or hereafter outstanding, return any
                  capital to its stockholders, or make any distribution of their
                  assets to their stockholders as such, except the foregoing
                  shall not apply to dividends from any Subsidiary to the
                  Borrowers or from Deep Seas to Atwood or to the redemption of
                  rights to purchase Atwood's Series A Junior Participating
                  Preferred Stock, no par value, at $0.01 per right pursuant to
                  the terms of the Atwood Oceanics, Inc. Rights Agreement dated
                  October 18, 2002."

                  (c) Subsection 12(o) of the Credit Agreement is hereby amended
         by the addition of the new sentence at the end thereof:

                           "Notwithstanding anything herein to the contrary,
                  upon ten (10) days prior written notice to Agent, Atwood may
                  amend its Restated Articles of Incorporation (as amended from
                  time to time) or take similar action to establish a series of
                  shares or may designate the rights and preferences of an
                  existing series of shares."

         6. Except to the extent its provisions are specifically amended,
modified or superseded by this First Amendment, the representations, warranties
and affirmative and negative covenants of the Borrowers contained in the Credit
Agreement are incorporated herein by reference for all purposes as if copied
herein in full. The Borrowers hereby restate and reaffirm each and every term
and provision of the Credit Agreement, as amended, including, without
limitation, all representations, warranties and affirmative and negative
covenants (except to the extent that such representations and warranties related
solely to an earlier date). Except to the extent its provisions are specifically
amended, modified or superseded by this First Amendment, the Credit Agreement,
as amended, and all terms and provisions thereof shall remain in full force and
effect, and the same in all respects are confirmed and approved by the Borrowers
and the Banks.


                                      -5-
<PAGE>

         7. This First Amendment shall be effective as of the date first above
written, but only upon the satisfaction of the conditions precedent set forth in
Paragraph 8 hereof (the "First Amendment Effective Date").

         8. The obligations of Banks under this First Amendment shall be subject
to the following conditions precedent:

                  (a) Execution and Delivery. The Borrowers shall have executed
         and delivered this First Amendment, and such additional Security
         Instruments required by the Banks, and other required documents, all in
         form and substance satisfactory to the Agent;

                  (b) Legal Opinions. The Agent shall have received from
         Borrowers' U.S. legal counsel a favorable legal opinion in form and
         substance satisfactory to the Agent;

                  (c) Corporate Resolutions. The Agent shall have received
         appropriate certified corporate resolutions of Atwood and the general
         partner of Deep Seas;

                  (d) Good Standing. The Agent shall have received evidence of
         existence and good standing for each Borrower and each Material
         Subsidiary;

                  (e) Articles of Incorporation and Bylaws. The Agent shall have
         received copies of any amendments to the Articles of Incorporation of
         Atwood and each Material Subsidiary made since February 20, 2002,
         certified by the Secretary of State of the State of its incorporation,
         and copies of any amendment to the bylaws of Atwood and each Material
         Subsidiary made since February 20, 2002 certified by Atwood and each
         Material Subsidiary as being true, correct and complete;

                  (f) Incumbency. The Agent shall have received a signed
         certificate of each Borrower (in the case of Deep Seas, of its general
         partner), certifying the names of the officers or other representatives
         of each Borrower authorized to sign loan documents on behalf of such
         Borrower, together with the true signatures of each such officer. The
         Agent may conclusively rely on such certificate until the Agent
         receives a further certificate of either Borrower canceling or amending
         the prior certificate and submitting signatures of the officers or
         other representatives, named in such further certificate;

                  (g) Partnership Agreement. The Agent shall have received a
         copy of any amendment to the Partnership Agreement of Deep Seas made
         since February 20, 2002 certified by the general partner of Deep Seas
         as being a true, correct and complete copy thereof;

                  (h) Confirmation of Class. The Agent shall have received
         satisfactory confirmation of class certificate for the Rigs from the
         American Bureau of Shipping dated within thirty (30) days of the
         Effective Date showing the Rigs to be classified as Maltese Cross A1
         Column Self Elevating Drilling Units dated within thirty (30) days of
         the Effective Date;


                                      -6-
<PAGE>

                  (i) Payment of Fees. The Agent shall have received payment in
         full of all fees due at the Effective Date;

                  (j) Insurance. Agent shall have received copies of all of
         Borrowers' insurance on the Rigs, including but not limited to hull and
         machinery insurance, protection and indemnity insurance and pollution
         insurance, all in form and substance satisfactory to the Agent and its
         insurance consultant;

                  (k) Representations and Warranties. The representations and
         warranties of the Borrowers under this First Amendment are true and
         correct in all material respects as of such date, as if then made
         (except to the extent that such representations and warranties related
         solely to an earlier date);

                  (l) No Event of Default. No Event of Default shall have
         occurred and be continuing nor shall any event have occurred or failed
         to occur which, with the passage of time or service of notice, or both,
         would constitute an Event of Default.

                  (m) Other Documents. The Agent shall have received such other
         instruments and documents incidental and appropriate to the transaction
         provided for herein as the Agent or its counsel may reasonably request,
         and all such documents shall be in form and substance satisfactory to
         the Agent;

                  (n) Legal Matters. All legal matters incident to the
         consummation of the transactions contemplated hereby shall be
         reasonably satisfactory to special counsel for the Agent retained at
         the expense of Borrowers.

         9. Borrowers hereby represent and warrant that all factual information
heretofore and contemporaneously furnished by or on behalf of Borrowers to Agent
for purposes of or in connection with this First Amendment does not contain any
untrue statement of a material fact or omit to state any material fact necessary
to keep the statements contained herein or therein from being materially
misleading. Each of the foregoing representations and warranties shall
constitute a representation and warranty of Borrowers made under the Credit
Agreement, and it shall be an Event of Default if any such representation and
warranty shall prove to have been incorrect or false in any material respect at
the time given. Each of the representations and warranties made under the Credit
Agreement (including those made herein) shall survive and not be waived by the
execution and delivery of this First Amendment or any investigation by Banks.

         10. The Borrowers agree to indemnify and hold harmless the Banks and
their respective officers, employees, agents, attorneys and representatives
(singularly, an "Indemnified Party", and collectively, the "Indemnified
Parties") from and against any loss, cost, liability, damage or expense
(including the reasonable fees and out-of-pocket expenses of counsel to the
Bank, including all local counsel hired by such counsel) ("Claim") incurred by
the Banks in investigating or preparing for, defending against, or providing
evidence, producing documents or taking any other action in respect of any
commenced or threatened litigation, administrative proceeding or investigation
under any federal securities law, federal or state environmental law, or any
other statute of any jurisdiction, or any regulation, or at common law or
otherwise, which


                                      -7-
<PAGE>

is alleged to arise out of or is based upon any acts, practices or omissions or
alleged acts, practices or omissions of the Borrowers or their agents or arises
in connection with the duties, obligations or performance of the Indemnified
Parties in negotiating, preparing, executing, accepting, keeping, completing,
countersigning, issuing, selling, delivering, releasing, assigning, handling,
certifying, processing or receiving or taking any other action with respect to
the Loan Documents and all documents, items and materials contemplated thereby
even if any of the foregoing arises out of an Indemnified Party's ordinary
negligence. The indemnity set forth herein shall be in addition to any other
obligations or liabilities of the Borrowers to the Banks hereunder or at common
law or otherwise, and shall survive any termination of this First Amendment, the
expiration of the Loan and the payment of all indebtedness of the Borrowers to
the Banks hereunder and under the Notes, provided that the Borrowers shall have
no obligation under this section to the Banks with respect to any of the
foregoing arising out of the gross negligence or willful misconduct of the
Banks. If any Claim is asserted against any Indemnified Party, the Indemnified
Party shall endeavor to notify the Borrowers of such Claim (but failure to do so
shall not affect the indemnification herein made except to the extent of the
actual harm caused by such failure). The Indemnified Party shall have the right
to employ, at the Borrowers' expense, counsel of the Indemnified Parties'
choosing and to control the defense of the Claim. The Borrowers may at their own
expense also participate in the defense of any Claim. Each Indemnified Party may
employ separate counsel in connection with any Claim to the extent such
Indemnified Party believes it reasonably prudent to protect such Indemnified
Party. THE PARTIES INTEND FOR THE PROVISIONS OF THIS SECTION TO APPLY TO AND
PROTECT EACH INDEMNIFIED PARTY FROM THE CONSEQUENCES OF STRICT LIABILITY IMPOSED
OR THREATENED TO BE IMPOSED ON ANY INDEMNIFIED PARTY AS WELL AS FROM THE
CONSEQUENCES OF ITS OWN NEGLIGENCE, WHETHER OR NOT THAT NEGLIGENCE IS THE SOLE,
CONTRIBUTING, OR CONCURRING CAUSE OF ANY CLAIM.

         11. This First Amendment may be executed in any number of counterparts
and all of such counterparts taken together shall be deemed to constitute one
and the same instrument.

         12. WRITTEN CREDIT AGREEMENT. THE CREDIT AGREEMENT, AS AMENDED BY THIS
FIRST AMENDMENT REPRESENTS THE FINAL AGREEMENT BETWEEN AND AMONG THE PARTIES AND
MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL
AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN AND
AMONG THE PARTIES.

         IN WITNESS WHEREOF, the parties have caused this First Amendment to
Amended and Restated Credit Agreement to be duly executed as of the date first
above written.

                                       BORROWERS:
                                       ---------

                                       ATWOOD OCEANICS, INC.,
                                       a Texas corporation

                                       By:  /s/James M. Holland
                                           ---------------------------
                                           James M. Holland
                                           Senior Vice President


                                      -8-
<PAGE>


                                       ATWOOD DEEP SEAS, LTD.,
                                       a Texas limited partnership

                                       By:  Atwood Hunter Co.,
                                           ----------------------------
                                           its general partner

                                           By:  /s/James M. Holland
                                               ------------------------
                                               James M. Holland
                                               Vice President


                                      -9-
<PAGE>


                                       BANKS:

                                       BANK ONE, NA, a national
                                       banking association (Main
                                       Office Chicago) as a Bank
                                       and as Administrative Agent



                                       By:  /s/Kenneth J. Fatur
                                           -----------------------------
                                           Kenneth J. Fatur
                                           Director, Capital Markets


                                      -10-
<PAGE>

                                       CREDIT LYONNAIS, NEW YORK BRANCH
                                       as a Bank and as Syndication Agent



                                       By:
                                          ------------------------------------
                                       Name:
                                            ----------------------------------
                                       Title:
                                             ---------------------------------


                                      -11-
<PAGE>


                                       FORTIS CAPITAL CORP.
                                       as a Bank and as Syndication Agent


                                       By:     /s/Suein Engh
                                              ---------------------
                                       Name:   Suein Engh
                                              ---------------------
                                       Title:  Managing Director
                                              ---------------------


                                       By:     /s/Chr. Tobias Backer
                                              -------------------------
                                       Name:   Chr. Tobias Backer
                                              -------------------------
                                       Title:  Vice President
                                              -------------------------


                                      -12-
<PAGE>


                                       NORDEA, ACTING THROUGH NORDEA BANK
                                       FINLAND PLC, NEW YORK BRANCH, as a Bank
                                       and as Documentation Agent


                                       By:     /s/Anne Engen
                                              -------------------------
                                       Name:   Anne Engen
                                              -------------------------
                                       Title:  Vice President
                                              -------------------------


                                       By:     /s/Ronny Bjornadal
                                              -------------------------
                                       Name:   Ronny Bjornadal
                                              -------------------------
                                       Title:  Vice President
                                              -------------------------


                                      -13-
<PAGE>


                                       THE BANK OF TOKYO-MITSUBISHI, LTD.


                                       By:
                                          -----------------------------------
                                       Name:
                                            ---------------------------------
                                       Title:
                                             --------------------------------


                                      -14-
<PAGE>


                                       CREDIT AGRICOLE INDOSUEZ


                                       By:     /s/Isabello Billecocq
                                              ---------------------------
                                       Name:   Isabello Billecocq
                                              ---------------------------
                                       Title:  Assistant Vice President
                                              ---------------------------


                                       By:     /s/Maryvonne Dourver
                                              ---------------------------
                                       Name:   Maryvonne Dourver
                                              ---------------------------
                                       Title:  Vice President
                                              ---------------------------


                                      -15-
<PAGE>


                             NATEXIS BANQUES POPULAIRES


                             By:     /s/Timothy L. Polvado
                                    -------------------------------------
                             Name:   Timothy L. Polvado
                                    -------------------------------------
                             Title:  Vice President and General Manager
                                    -------------------------------------


                             By:     /s/Renaud J. d'Herbes
                                    -------------------------------------
                             Name:   Renaud J. d'Herbes
                                    -------------------------------------
                             Title:  Senior Vice President and Regional
                                    -------------------------------------
                                     Manager
                                    -------------------------------------


                                      -16-
<PAGE>


                                       MIZUHO CORPORATE BANK


                                       By:     /s/Hirofumi Susano
                                              ---------------------------
                                       Name:   Hirofumi Susano
                                              ---------------------------
                                       Title:  Senior Vice President
                                              ---------------------------


                                      -17-
<PAGE>


                                       WHITNEY NATIONAL BANK


                                       By:     /s/Harry C. Stahel
                                              ---------------------------
                                       Name:   Harry C. Stahel
                                              ---------------------------
                                       Title:  Senior Vice President
                                              ---------------------------


                                      -18-