Exhibit 5.1


                                   March 11, 2004

Akamai Technologies, Inc.
8 Cambridge Center
Cambridge, Massachusetts 02142


         Re:  Registration Statement on Form S-3
              ----------------------------------

Ladies and Gentlemen:

         This opinion is furnished to you in connection with a Registration
Statement on Form S-3 (the "Registration Statement") to be filed with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended (the "Securities Act"), for the registration of an aggregate
of $200,000,000 of 1.0% Convertible Senior Notes due 2033 (the "Notes") and the
underlying shares of common stock issuable upon conversion of such Notes (the
"Shares" and, together with the Notes, the "Securities") of Akamai Technologies,
Inc., a Delaware corporation (the "Company"). The Securities are being
registered on behalf of certain securityholders of the Company.

         The Notes were issued pursuant to an Indenture, dated as of December
12, 2003 (the "Indenture"), between the Company and U.S. Bank National
Association as trustee (the "Trustee").

         We are acting as counsel for the Company in connection with the
registration by the Company of the Securities. We have examined signed copies of
the Registration Statement to be filed with the Commission. We have also
examined and relied upon the Registration Rights Agreement, dated as of December
12, 2003, the Indenture, resolutions adopted by the board of directors of the
Company as provided to us by the Company, the Certificate of Incorporation and
By-Laws of the Company, each as restated and/or amended to date, and such other
documents as we have deemed necessary for purposes of rendering the opinions
hereinafter set forth.

         In our examination of the foregoing documents, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity to original documents of all documents submitted to
us as copies, the authenticity of the originals of such latter documents and the
legal competence of all signatories to such documents.

         We assume that the appropriate action will be taken, prior to the offer
and sale of the Securities, to register and qualify the Securities for sale
under all applicable state securities or "blue sky" laws.

         We express no opinion herein as to the laws of any state or
jurisdiction other than the state laws of the State of New York, the General
Corporation Law of the State of Delaware and the federal laws of the United
States of America.




Akamai Technologies, Inc.
March 11, 2004
Page 2


         Our opinions below are qualified to the extent that they may be subject
to or affected by (i) applicable bankruptcy, insolvency, reorganization,
moratorium, usury, fraudulent conveyance or similar laws affecting the rights of
creditors generally, (ii) duties and standards imposed on creditors and parties
to contracts, including, without limitation, requirements of good faith,
reasonableness and fair dealing, (iii) statutory or decisional law concerning
recourse of creditors to security in the absence of notice or hearing, or (iv)
general equitable principles. We express no opinion as to the enforceability of
any provision of any of the Notes that purports to select the laws by which it
or any other agreement or instrument is to be governed. Furthermore, we express
no opinion as to the availability of any equitable or specific remedy, or as to
the successful assertion of any equitable defense, upon any breach of any
agreements or documents or obligations referred to therein, or any other
matters, inasmuch as the availability of such remedies or defenses may be
subject to the discretion of a court. In addition, we express no opinion with
respect to the enforceability of any provision of the Securities requiring the
payment of interest on overdue interest.

         We also express no opinion herein as to any provision of any agreement
(a) which may be deemed to or construed to waive any right of the Company, (b)
to the effect that rights and remedies are not exclusive, that every right or
remedy is cumulative and may be exercised in addition to or with any other right
or remedy and does not preclude recourse to one or more other rights or
remedies, (c) relating to the effect of invalidity or unenforceability of any
provision of the Indenture on the validity or enforceability of any other
provision thereof, (d) requiring the payment of penalties, consequential damages
or liquidated damages, (e) which is in violation of public policy, including,
without limitation, any provision relating to indemnification and contribution
with respect to securities law matters, (f) purporting to indemnify any person
against his, her or its own negligence or intentional misconduct, (g) which
provides that the terms of the Indenture may not be waived or modified except in
writing, or (h) relating to choice of law or consent to jurisdiction.

         Based upon and subject to the foregoing, we are of the opinion that (i)
the Notes have been duly authorized and were validly issued, executed and
delivered by the Company and, assuming they have been authenticated by the
Trustee in the manner provided by the Indenture, are valid and binding
obligations of the Company, enforceable against the Company in accordance with
their terms, and entitled to the benefits provided by the Indenture; and (ii)
the Shares issuable upon conversion of the Notes have been duly authorized by
the Company, and, when issued upon conversion of the Notes in accordance with
the terms of the Indenture, will be validly issued, fully paid and
nonassessable.

         It is understood that this opinion is to be used only in connection
with the offer and sale of the Securities while the Registration Statement is in
effect.

         Please note that we are opining only as to the matters expressly set
forth herein, and no opinion should be inferred as to any other matters. This
opinion is based upon currently existing statutes, rules, regulations and
judicial decisions, and we disclaim any obligation to advise you of any change
in any of these sources of law or subsequent legal or factual developments which
might affect any matters or opinions set forth herein.



Akamai Technologies, Inc.
March 11, 2004
Page 3


         We hereby consent to the filing of this opinion with the Commission as
an exhibit to the Registration Statement in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Securities Act and to the use of our
name therein and in the related Prospectus under the caption "Validity of
Securities." In giving such consent, we do not hereby admit that we are in the
category of persons whose consent is required under Section 7 of the Securities
Act or the rules and regulations of the Commission.

                                        Very truly yours,


                                        /s/ Hale and Dorr LLP
                                        ---------------------------
                                        HALE AND DORR LLP