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                                                                  EXHIBIT 10.3

                             RSL COMMUNICATIONS PLC
                                    As Issuer


                            RSL COMMUNICATIONS, LTD.
                                  As Guarantor

                              RSL COM U.S.A., INC.
                             As Subsidiary Guarantor



                                       TO
                            THE CHASE MANHATTAN BANK,
                                   As Trustee


                              --------------------


                          SECOND SUPPLEMENTAL INDENTURE


                          Dated as of February 22, 2000


                              --------------------


                          12 1/5% SENIOR NOTES DUE 2006


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                          SECOND SUPPLEMENTAL INDENTURE

                  SECOND SUPPLEMENTAL INDENTURE, dated as of February 22, 2000
(the "Second Supplemental Indenture"), between RSL Communications PLC, a United
Kingdom corporation, as issuer (hereinafter called the "Issuer"), RSL
Communications, Ltd., a Bermuda corporation, as guarantor (hereinafter called
the "Guarantor"), RSL COM U.S.A., Inc., a Delaware corporation, as guarantor
(hereinafter called the "Subsidiary Guarantor"), and The Chase Manhattan Bank, a
corporation duly organized and existing under the laws of the State of New York,
as Trustee (hereinafter called the "Trustee").

                  Capitalized terms used herein but not otherwise defined herein
shall have the meanings given to such terms in the Indenture, dated as of
October 3, 1996, between the Company, the Guarantor and the Trustee (the
"Indenture").

                                    Recitals

                  WHEREAS, the Issuer, the Guarantor and the Trustee entered
into the Indenture pursuant to which the Issuer issued its 12 1/5% Senior Notes
due 2006 (the "Notes");

                  WHEREAS, the Issuer desires to issue its euro denominated
senior notes due 2010 (the "Euro Notes") and its dollar denominated senior notes
due 2010 (the "Dollar Notes") in an aggregate principal amount of up to
approximately $230,000,000 (or the U.S. dollar equivalent);

                  WHEREAS, the Subsidiary Guarantor has substantially benefited
from the issuance of the Notes and expects to substantially benefit from the
issuance of the Dollar Notes and the Euro Notes;

                  WHEREAS, to facilitate the offering of the Dollar Notes and
the Euro Notes, the Subsidiary Guarantor is fully, unconditionally and
irrevocably guaranteeing, on an unsubordinated basis, all of the obligations of
the Issuer under the Dollar Notes, the Euro Notes and the indentures pursuant to
which they will be issued;

                  WHEREAS, Section 5.07 of the Indenture provides that the
Subsidiary Guarantor may not guarantee any Indebtedness of the Issuer unless the
Subsidiary Guarantor simultaneously executes and delivers a supplemental
indenture to the Indenture providing for a guarantee of payment of the Notes on
the terms provided herein;


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                  WHEREAS, the Boards of Directors of the Issuer, the Guarantor
and the Subsidiary Guarantor have authorized the execution of the Second
Supplemental Indenture and its delivery to the Trustee;

                  WHEREAS, the Company and the Guarantor have delivered an
Opinion of Counsel to the Trustee pursuant to Section 9.05 of the Indenture;

                  WHEREAS, all other actions necessary to make this Second
Supplemental Indenture a legal, valid and binding obligation of the parties
hereto in accordance with its terms and the terms of the Indenture have been
performed; and

                  WHEREAS, the Issuer, the Guarantor, the Subsidiary Guarantor
and the Trustee desire to enter into, execute and deliver this Second
Supplemental Indenture in compliance with the provisions of the Indenture.

                  NOW, THEREFORE, the Issuer, the Guarantor and the Trustee
hereby agree as follows for the benefit of each other and for the equal and
ratable benefit of the Holders of the Notes:

                                   Article I
                              SUBSIDIARY GUARANTEE

                  SECTION 1.01. Guarantee. Subject to the provisions of this
Article One, the Subsidiary Guarantor hereby fully, unconditionally and
irrevocably guarantees to each Holder and to the Trustee on behalf of the
Holders: (i) the due and punctual payment of the principal of, premium, if any,
on and interest (including Special Interest) on each Note, when and as the same
shall become due and payable, whether at maturity, by acceleration or otherwise,
the due and punctual payment of interest on the overdue principal of and
interest, if any, on the Notes, to the extent lawful, and the due and punctual
performance of all other obligations of the Issuer to the Holders or the
Trustee, all in accordance with the terms of such Note and this Indenture and
(ii) in the case of any extension of time of payment or renewal of any Notes or
any of such other obligations, that the same will be promptly paid in full when
due or performed in accordance with the terms of the extension or renewal, at
Stated Maturity, by acceleration or otherwise. The Subsidiary Guarantor hereby
waives diligence, presentment, demand of payment, filing of claims with a court
in the event of merger or bankruptcy of the Issuer, any right to require a
proceeding first against the Issuer, the benefit of discussion, protest or
notice with respect to any such Note or the debt evidenced thereby and all
demands whatsoever, and covenants that this Guarantee will not be discharged as
to any such Note except by payment in full of the principal thereof and interest
thereon and as provided in Section 8.01 and Section 8.02 (subject to Section
8.06) of the Indenture. The maturity of the obligations guaranteed hereby may be
accelerated as provided in Article Six of the Indenture for the purposes of this
Article One. In the event of any declaration of

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acceleration of such obligations as provided in Article Six of the Indenture,
such obligations (whether or not due and payable) shall forthwith become due and
payable by the Subsidiary Guarantor for the purpose of this Article One. In
addition, without limiting the foregoing provisions, upon the effectiveness of
an acceleration under Article Six of the Indenture, the Trustee shall promptly
make a demand for payment on the Notes under the Guarantee provided for in this
Article One.

                  If the Trustee or the Holder of any Note is required by any
court or otherwise to return to the Issuer or the Subsidiary Guarantor, or any
custodian, receiver, liquidator, trustee, sequestrator or other similar official
acting in relation to the Issuer, the Guarantor or the Subsidiary Guarantor, any
amount paid to the Trustee or such Holder in respect of a Note, this Guarantee,
to the extent theretofore discharged, shall be reinstated in full force and
effect. The Subsidiary Guarantor further agrees, to the fullest extent that the
Subsidiary Guarantor may lawfully do so, that, as between the Subsidiary
Guarantor, on the one hand, and the Holders and the Trustee, on the other hand,
the maturity of the obligations guaranteed hereby may be accelerated as provided
in Article Six of the Indenture for the purposes of this Guarantee,
notwithstanding any stay, injunction or other prohibition extant under any
applicable bankruptcy law preventing such acceleration in respect of the
obligations guaranteed hereby.

                  Until such time as the Notes are fully and finally paid,
including all interest, premium, principal and liquidated damages with respect
thereto, the Subsidiary Guarantor hereby irrevocably waives any claim or other
rights which they may now or hereafter acquire against the Issuer that arise
from the existence, payment, performance or enforcement of their obligations
under this Guarantee and this Indenture, including, without limitation, any
right of subrogation, reimbursement, exoneration, contribution, indemnification,
any right to participate in any claim or remedy of the Holders against the
Issuer or any collateral which any such Holder or the Trustee on behalf of such
Holder hereafter acquires, whether or not such claim, remedy or right arises in
equity, or under contract, statute or common law, including, without limitation,
the right to take or receive from the Issuer, directly or indirectly, in cash or
other property or by setoff or in any other manner, payment or Note on account
of such claim or other rights. If any amount shall be paid to the Subsidiary
Guarantor in violation of the preceding sentence and the principal of, premium,
if any, and accrued interest on the Notes shall not have been paid in full, such
amount shall be deemed to have been paid to the Subsidiary Guarantor for the
benefit of, and held in trust for the benefit of, the Holders, and shall
forthwith be paid to the Trustee for the benefit of the Holders to be credited
and applied upon the principal of, premium, if any, and accrued interest on the
Notes. The Subsidiary Guarantor acknowledges that the Subsidiary Guarantor has
received and will receive direct and indirect benefits from the issuance of the
Notes pursuant to the Indenture and that the waivers set forth in this Section
1.01 are knowingly made in contemplation of such benefits.

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                  The Guarantee set forth in this Section 1.01 shall not be or
become valid or obligatory for any purpose with respect to a Note unless the
certificate of authentication on such Note shall have been signed by or on
behalf of the Trustee.

                  SECTION 1.02. Obligations Unconditional. Subject to Section
1.05, nothing contained in this Article One or elsewhere in the Indenture or in
the Notes is intended to or shall impair, as among the Subsidiary Guarantor and
the holders of the Notes, the obligation of the Subsidiary Guarantor, which is
absolute and unconditional, upon failure by the Issuer, to pay to the holders of
the Notes the principal of, premium, if any, and interest on the Notes as and
when the same shall become due and payable in accordance with their terms, or is
intended to or shall affect the relative rights of the holders of the Notes and
creditors of the Subsidiary Guarantor, nor shall anything herein or therein
prevent the holder of any Notes or the Trustee on their behalf from exercising
all remedies otherwise permitted by applicable law upon default under this
Indenture.

                  Without limiting the foregoing, nothing contained in this
Article One will restrict the right of the Trustee or the holders of the Notes
to take any action to declare the Guarantee to be due and payable prior to the
Stated Maturity of the Notes pursuant to Section 6.02 of the Indenture or to
pursue any rights or remedies hereunder.

                  SECTION 1.03. Notice to Trustee. The Subsidiary Guarantor
shall give prompt written notice to the Trustee of any fact known to the
Subsidiary Guarantor which would prohibit the making of any payment to or by the
Trustee in respect of the Guarantee pursuant to the provisions of this Article
One.

                  SECTION 1.05. Release of the Subsidiary Guarantor. The
Subsidiary Guarantor shall be automatically and unconditionally released and
discharged from its obligations under this Guarantee (i) upon any sale, exchange
or transfer, to any Person not an Affiliate of the Guarantor, of all of the
Guarantor's and each Restricted Subsidiary's Capital Stock in, or all or
substantially all the assets of, the Subsidiary Guarantor (which sale, exchange
or transfer is not prohibited by the Indenture) or (ii) at any time, so long as
in the case of this clause (ii) Standard & Poor's Corporation, or any successor,
is notified by the Issuer of the proposed termination of the Guarantee of the
Subsidiary Guarantor and advises the Issuer that such termination would not
result in a downgrade of the rating on the Notes or placement of the Notes on
creditwatch with negative implications.

                                   Article II
                                  MISCELLANEOUS

                  SECTION 2.01. Trustee's Disclaimer. The Trustee shall not be
responsible for and makes no representation as to the validity or adequacy of
this Second

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Supplemental Indenture or the Notes, and it shall not be responsible for any
statement of the Issuer or the Guarantor or the Subsidiary Guarantor in this
Second Supplemental Indenture.

                  SECTION 2.02. Ratification. Except as hereby expressly
amended, the Indenture and the Notes issued thereunder are in all respects
ratified and confirmed and all the terms, conditions and provisions thereof
shall remain in full force and effect. Upon execution, this Second Supplemental
Indenture shall form a part of the Indenture and the Second Supplemental
Indenture and the Indenture shall be read, taken and construed as one and the
same instrument for all purposes, and every holder of Notes heretofore or
hereafter authenticated and delivered under the Indenture shall be bound hereby.

                  SECTION 2.03. Effectiveness. This Second Supplemental
Indenture shall become effective as of the date first above written.

                  SECTION 2.05. Governing Law. THIS SECOND SUPPLEMENTAL
INDENTURE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF NEW YORK, AS APPLIED TO CONTRACTS MADE AND PERFORMED WITHIN THE STATE
OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF CONFLICT OF LAWS.

                  SECTION 2.05. Counterpart Originals. The parties may sign any
number of copies of this Second Supplemental Indenture. Each signed copy shall
be an original, but all of them together represent the same agreement. One
signed copy is enough to prove this Second Supplemental Indenture.

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                                   SIGNATURES

                  IN WITNESS WHEREOF, the parties hereto have caused this Second
Supplemental Indenture to be duly executed, and their respective corporate seals
to be hereunto affixed and duly attested, all as of the day and year first above
written.

The Company Seal of RSL COMMUNICATIONS PLC
was hereto affixed in the presence of:



[Seal]

                                             RSL COMMUNICATIONS PLC,



                                             By: /s/ Donald R. Shassian
                                                 ------------------------------
                                                 Name:
                                                 Title:


                                             By: /s/ Margaret B. Niche
                                                 ------------------------------
                                                 Name:
                                                 Title:


                                             THE CHASE MANHATTAN BANK



                                             By: /s/ Robert Peschler
                                                 ------------------------------


                                             RSL COMMUNICATIONS, LTD.,



                                             By: /s/ Donald R. Shassian
                                                 ------------------------------
                                                 Name:
                                                 Title:


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                                             RSL COM U.S.A., INC.



                                             By: /s/ Joel Beckoff
                                                 ------------------------------
                                                 Name:
                                                 Title: