<PAGE>
[Letterhead of Field Fisher Waterhouse]
RSL Communications plc
RSL Communications, Ltd
810 Seventh Avenue
39th Floor
New York
17 July 2000
Dear Sirs,
RSL Communications plc (the "Issuer") and RSL Communications, Ltd (together the
"Companies")
1. Introduction
We are Solicitors of the Supreme Court of Judicature of England and Wales and
have acted as English legal advisers to the Companies in connection with an
offer to exchange up to US$100,000,000 aggregate principal amount of the
Issuer's 12 7/8% Senior Dollar Notes due 2010 and up to (Euro) 100,000,000
aggregate principal amount of the Issuer's 12 7/8% Senior Euro Notes due 2010
(the "New Notes") for US$100,000,000 aggregate principal amount of the Issuer's
outstanding 12 7/8% Senior Dollar Notes due 2010 and (Euro) 100,000,000
aggregate principal amount of its outstanding 12 7/8% Senior Euro Notes due 2010
(the "Old Notes") issued on 22 February 2000 (the "Exchange Offer") as described
in the Form S-4 Registration Statement of the Companies filed with the
Securities and Exchange Commission on 17 July 2000 (the "Registration
Statement").
<PAGE>
2. Opinion
On the basis of the assumptions and qualifications set out below we are of the
opinion that:
(a) When the Registration Statement has become effective under the US
Securities Act of 1933 as amended and the New Notes have been duly issued
and exchanged for the Old Notes in the manner described in the Registration
Statement, that the New Notes will constitute legal, valid and binding
obligations of the Issuer enforceable in accordance with their terms.
(b) The statements set forth in the Registration Statement under the caption
"Certain United Kingdom Tax Considerations", insofar as they purport to
describe the provisions of the laws referred to therein, are accurate and
fair.
(c) The statements set forth in the Registration Statement under the captions
"Service of Process and Enforcement of Liabilities"; "Effects of
incorporation under United Kingdom corporate law" and "Certain UK Related
Regulatory Issues" to the extent such statements relate to matters of law
or regulations of England or the United Kingdom, as the case may be, are
fair and accurate in all material respects, and to the best of our
knowledge nothing has been omitted from such statements which would make
the same misleading in any material respect.
3. Documents
In connection with the giving of this Opinion, we have examined the "Summary
Description of the New Notes" as set out in the Registration Statement (the
"Summary") and such other documents as we have deemed necessary for the purposes
of this Opinion. However, we have not examined the New Notes and this Opinion is
given only to the extent that the Summary comprises an
<PAGE>
accurate and complete summary of the contents of the New Notes.
4. Assumptions
For the purposes of this Opinion, we have assumed without investigation:
(a) The genuineness of all signatures, the authenticity of all documents
submitted to us and the conformity with the originals of all documents
submitted to us as copies or facsimiles.
(b) Where any liability or obligation, right or benefit of a holder of the New
Notes is dependent upon the satisfaction of conditions precedent, that such
conditions have been or will be duly and properly satisfied.
(c) Since the Old Notes were issued, no party has by its words, actions or
conduct waived any of the rights it may have under the Old Notes or given
rise to an estoppal against such party so preventing it from relying on any
particular provision.
(d) There are no agreements or arrangements in existence, made prior to the
Exchange Offer, which affect the enforceability of the Exchange Offer or
the New Notes or the Old Notes in accordance with their terms.
(e) There are no provisions of the laws of any jurisdiction outside England and
Wales which would have any adverse implication in relation to the opinions
expressed in this Opinion.
(f) So far as the laws of the United States of America and/or any state or
district of the United States of America are concerned, any document
referred to in this Opinion and executed by the Companies (or either of
them) constitutes legal, valid and binding obligations of the Company and
that such
<PAGE>
laws do not qualify or affect the opinions expressed in this Opinion.
(g) Any documents referred to in this Opinion have been duly authorised,
executed and delivered by and are within the capacity and powers of the
respective parties thereto and that, where those documents (or any of them)
are to be performed in, or their validity or enforceability may fall to be
determined in accordance with the laws of, jurisdictions outside England,
they are not illegal or contrary to public policy under the laws of such
jurisdictions.
(h) There are no facts or circumstances in existence and no events have
occurred which would render the Old Notes or the New Notes void or voidable
or repudiated or frustrated or capable of recission for any reason, and in
particular (but without limitation) by reason of lack of consideration or
any fraud or misrepresentation on the part of any of the parties thereto.
5. Qualifications
Our qualifications are as follows:
(a) This Opinion is limited to English law as applied by the English courts and
given on the basis that it will be governed and construed in accordance
with English law.
(b) The term "enforceable" as used in paragraph 2(a) above means that the
obligations assumed under the relevant documents are of a type which the
English courts enforce. It does not mean that those obligations will
necessarily be enforced in all circumstances in accordance with their
terms. In particular:
(i) enforcement may be limited by dissolution, bankruptcy, insolvency,
liquidation, reorganisation and other laws of general
<PAGE>
application relating to or affecting the rights of creditors;
(ii) enforcement may be limited by general principles of equity - for
example, equitable remedies may not be available where damages are
considered to be an adequate remedy;
(iii) claims may become barred under the Limitation Acts or may be or
become subject to defences of set-off or counterclaim;
(iv) where obligations are to be performed in a jurisdiction outside
England, they may not be enforceable in England to the extent that
performance will be illegal or contrary to public policy under the
laws of that jurisdiction.
(c) The English Courts have power to award a judgement in foreign currency, but
will not necessarily do so.
(d) We express no opinion as to the enforceability outside England of any of
the documents referred to in this Opinion.
6. General
(a) The headings in this Opinion are for reference only and do not affect its
interpretation.
(b) This Opinion is for the sole benefit of the Companies and is not to be
transmitted to any other person or quoted or referred to in any public
document or filed with any governmental agency or other person without our
consent.
We consent to the filing of this Opinion as an exhibit to the Registration
Statement relating to the New Notes and to the references to us under the
headings "Legal Matters" and "Service of Process and Enforcement of Liabilities"
in the Registration Statement.
<PAGE>
Yours faithfully
Field Fisher Waterhouse
