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                                                                     EXHIBIT 5.1



                                 June 30, 1999


Voyager.net, Inc.
4660 S. Hagadorn Road, Suite 320
East Lansing, MI 48823


     Re:  Legality of Securities to be Registered Under
          Registration Statement on Form S-1
          File No. 333-77917
          ------------------------------------------------------

Ladies and Gentlemen:

     This opinion is delivered in our capacity as counsel to Voyager.net, Inc.
(the "Company") in connection with the preparation and filing with the
Securities and Exchange Commission under the Securities Act of 1933, as amended,
of a Registration Statement on Form S-1 (the "Registration Statement"),
relating to 9,056,250 shares of common stock, par value $.0001 per share (the
"Registered Shares"), including 1,181,250 shares which the Underwriters (as
defined below) have options to purchase solely for the purpose of covering over-
allotments. Of the 9,056,250 Registered Shares, 7,008,750 shares (including
708,750 shares to cover the over-allotment option) are to be sold by the
Company (the "Company Shares") and 2,047,500 shares (including 472,500 shares to
cover the over-allotment option) are to be sold by certain selling stockholders
(the "Selling Stockholder Shares") to the several underwriters (the
"Underwriters") for whom Donaldson, Lufkin & Jenrette Securities Corporation
First Union Capital Markets Corp. and CIBC World Markets are acting as
representatives (the "Representatives") pursuant to an underwriting agreement to
be entered into between the Company and the Underwriters (the "Underwriting
Agreement").

     In connection with rendering this opinion, we have examined the form of the
proposed Underwriting Agreement being filed as an Exhibit to the Registration
Statement; the Certificate of Incorporation and By-laws of the Company, each as
amended to date; such records of the corporate proceedings of the Company as we
deemed material; and such other certificates, receipts, records and documents as
we considered necessary for the purpose of this opinion. In our examination, we
have assumed the genuineness of all signatures, the legal capacity of natural
persons, the authenticity of all documents submitted to us as certified,
photostatic or facsimile copies, the authenticity of the originals of such
copies and the authenticity of telephonic confirmations of public materials. As
to facts material to our opinion, we have relied upon certificates or telephonic
confirmations of public officials and certificates, documents, statements and
other information of the Company or representatives or officers thereof.

     We are attorneys admitted to practice in The Commonwealth of Massachusetts.
We express no opinion concerning the laws of any jurisdictions other than the
laws of the United
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Voyager,net Inc.
June 30, 1999
Page 2

States of America, the laws of The Commonwealth of Massachusetts and the
Delaware General Corporation Law.

     Based upon the foregoing, we are of the opinion that (A) when (i) the
Underwriting Agreement is completed (including the insertion therein of pricing
terms) and executed by the Company and on behalf of the Underwriters, and (ii)
the Company Shares are sold to the Underwriters and paid pursuant to the terms
of the Underwriting Agreement, the Company Shares will be duly authorized,
validly issued and fully paid and non-assessable by the Company under the
General Corporation Law of the State of Delaware (the "DGCL"), and (B) the
Selling Stockholders Shares are duly authorized, legally issued, fully paid and
non-assessable by the Company under the DGCL.

     The foregoing assumes that all requisite steps will be taken to comply with
the requirements of the Securities Act and applicable requirements of state laws
regulating the offer and sale of securities.

     We hereby consent to being named as counsel to the Company in the
Registration Statement, to the references therein to our firm under the caption
"Legal Matters" and to the inclusion of this opinion as an exhibit to the
Registration Statement.

                                    Very truly yours,

                                    /s/ Goodwin, Procter & Hoar LLP

                                    GOODWIN, PROCTER & HOAR LLP