1.875% Convertible Senior Notes due 2013 Registration Rights Agreement

Exhibit 10.70

SBA Communications Corporation

1.875% Convertible Senior Notes due 2013

Registration Rights Agreement

May 16, 2008

Deutsche Bank Securities Inc.,

Citigroup Global Markets Inc.,

Lehman Brothers Inc.

As Representatives of the several

    Initial Purchasers listed on

    Schedule 1 to the Purchase Agreement

c/o Deutsche Bank Securities Inc.

60 Wall Street New York, New York 10005

Ladies and Gentlemen:

SBA Communications Corporation, a Florida corporation (the “ Company ”), proposes to issue and sell to the initial purchasers listed on Schedule 1 to the Purchase Agreement (as defined below) (collectively, the “ Initial Purchasers ”), upon the terms and subject to the conditions set forth in a purchase agreement, dated May 12, 2008 (the “ Purchase Agreement ”), between the Company and you, as the Representatives of the Initial Purchasers, $500,000,000 aggregate principal amount of its 1.875% Convertible Senior Notes due 2013 (the “ Firm Notes ”) and, at the election of the Initial Purchasers, an additional $50,000,000 aggregate principal amount of the Company’s 1.875% Convertible Senior Notes due 2013 (the “ Additional Notes ” and, together with the Firm Notes, the “ Notes ”). The Notes will be convertible into fully paid, non-assessable shares of Class A common stock, par value $0.01 per share, of the Company on the terms, and subject to the conditions, set forth in the Indenture (as defined below). Capitalized terms used but not defined herein shall have the meanings given to such terms in the Purchase Agreement.

As an inducement to the Initial Purchasers to enter into the Purchase Agreement, and in satisfaction of a condition to the obligations of the Initial Purchasers thereunder, the Company agrees with the Initial Purchasers, for the benefit of the holders (including the Initial Purchasers) of the Notes and the Shares (as defined below) (collectively, the “ Holders ”), as follows:

For purposes of this Registration Rights Agreement the following terms shall have the following meanings:

(a) “ Additional Interest ” has the meaning assigned thereto in Section 2(d).

(b) “ Additional Notes ” has the meaning specified in the first paragraph of this Agreement.

(c) “ Agreement ” means this Registration Rights Agreement, as the same may be amended from time to time pursuant to the terms hereof.

(d) “ Business Day ” means any day other than a Saturday, a Sunday or a day on which banking institutions in New York, New York are authorized or required by law or executive order to remain closed.

(e) “ Closing Date ” means the first date on which any Notes are initially issued.

(f) “ Commission ” means the Securities and Exchange Commission, or any other federal agency at the time administering the Exchange Act or the Securities Act, whichever is the relevant statute for the particular purpose.

(g) “ Company ” has the meaning specified in the first paragraph of this Agreement.

(h) “ Deferral Notice ” has the meaning assigned thereto in Section 3(b).

(i) “ Deferral Period ” has the meaning assigned thereto in Section 3(b).

(j) “ Effective Period ” has the meaning assigned thereto in Section 2(a).

(k) “ Exchange Act ” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

(l) “ FINRA ” shall mean the Financial Industry Regulatory Authority.

(m) “ Firm Notes ” has the meaning specified in the first paragraph of this Agreement.

(n) “ Free Writing Prospectus ” means each free writing prospectus (as defined in Rule 405 under the Securities Act) prepared by or on behalf of the Company or used or referred to by the Company in connection with the sale of the Securities.

(o) “ Holder ” means each holder, from time to time, of Registrable Securities (including the Initial Purchasers).

(p) “ Indenture ” means the Indenture dated as of the date hereof between the Company and U.S. Bank National Association, as Trustee, pursuant to which the Notes are being issued, and in accordance with which Shares may be issued, as the same may be amended, supplemented, waived or otherwise modified from time to time in accordance with the terms thereof.

(q) “ Initial Purchasers ” has the meaning specified in the first paragraph of this Agreement.

(r) “ Issuer Information ” has the meaning set forth in Section 6(a) hereof.

(s) “ Material Event ” has the meaning assigned thereto in Section 3(b).

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(t) “ Majority Holders ” shall mean, on any date, holders of the majority of the Shares constituting Registrable Securities; for the purposes of this definition, Holders of Notes constituting Registrable Securities shall be deemed to be the Holders of the number of Shares into which such Notes are or would be convertible as of such date, assuming for this purpose that the Company has elected to satisfy its conversion obligation shares of Class A common stock, par value $0.01 per share, of the Company.

(u) “ Notes ” has the meaning specified in the first paragraph of this Agreement.

(v) “ Notice and Questionnaire ” means a written notice delivered to the Company containing substantially the information called for by the Form of Selling Securityholder Notice and Questionnaire attached as Annex A to the Offering Memorandum.

(w) “ Notice Holder ” means, on any date, any Holder that has delivered a Notice and Questionnaire to the Company prior to such date.

(x) “ Offering Memorandum ” means the Offering Memorandum dated May 12, 2008 relating to the offer and sale of the Securities.

(y) “ Person ” means a corporation, association, partnership, organization, business, individual, government or political subdivision thereof or governmental agency.

(z) “ Prospectus ” means the prospectus included in any Shelf Registration Statement, including any preliminary prospectus, and any such prospectus as amended or supplemented by any amendment or prospectus supplement, including post-effective amendments, and all materials incorporated by reference or explicitly deemed to be incorporated by reference in such Prospectus.

(aa) “ Purchase Agreement ” has the meaning specified in the first paragraph of this Agreement.

(bb) “ Registrable Securities ” means

(cc) “ Registration Default ” has the meaning assigned thereto in Section 2(d).

(dd) “ Registration Expenses ” has the meaning assigned thereto in Section 5.

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(ee) “ Rule 144 ,” “ Rule 405 ” and “ Rule 415 ” mean, in each case, such rule as promulgated under the Securities Act.

(ff) “ Securities ” means, collectively, the Notes and the Shares.

(gg) “ Securities Act ” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

(hh) “ Shares ” means the shares of Class A common stock of the Company, par value $0.01 per share, into which the Notes are convertible or that have been issued upon a conversion from Notes into Class A common stock of the Company.

(ii) “ Shelf Registration Statement ” means the shelf registration statement referred to in Section 2(a), as amended or supplemented by any amendment or supplement, including post-effective amendments, and all materials incorporated by reference or explicitly deemed to be incorporated by reference in such Shelf Registration Statement.

(jj) “ Special Counsel ” shall have the meaning assigned thereto in Section 5.

(kk) “ Trust Indenture Act ” means the Trust Indenture Act of 1939, as amended, or any successor thereto, and the rules, regulations and forms promulgated thereunder.

(ll) “ Trustee ” shall have the meaning assigned such term in the Indenture.

Unless the context otherwise requires, any reference herein to a “Section” or “clause” refers to a Section or clause, as the case may be, of this Agreement, and the words “herein,” “hereof” and “hereunder” and other words of similar import refer to this Agreement as a whole and not to any particular Section or other subdivision. Unless the context otherwise requires, any reference to a statute, rule or regulation refers to the same (including any successor statute, rule or regulation thereto) as it may be amended from time to time.

(a) (i) The Company agrees to use its reasonable best efforts to cause the Shelf Registration Statement to be declared effective no later than the 190 ^th calendar day following the Closing Date and (ii) subject to Section 3(b), the Company agrees to use its reasonable best efforts to keep the Shelf Registration Statement continuously effective until such time as there are no longer any Registrable Securities outstanding (the “Effective Period”); provided , however , that the Company’s obligation to file, have declared effective or maintain effectiveness of the Shelf Registration Statement shall be suspended to the extent that the Registrable Securities are eligible to be sold by a Person that is not affiliated with the Company without any volume or manner of sale restrictions pursuant to Rule 144 (or any other similar provision then in force (other than Rule 144A)) and no additional Interest shall accrue during any period the Company’s obligation has been so suspended.

(b) The Company further agrees that it shall cause the Shelf Registration Statement and the related Prospectus and any amendment or supplement thereto, as of the effective date of the Shelf Registration Statement or such amendment or supplement, (i) to comply in all material respects with the applicable requirements of the Securities Act; and (ii) not to contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein (in the case of the Prospectus, in the light of the circumstances under which they were made) not misleading, and the Company agrees to furnish to the Holders of the Registrable Securities copies of any supplement or amendment prior to its being used

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or promptly following its filing with the Commission; provided, however , that the Company shall have no obligation to deliver to Holders of Registrable Securities copies of any amendment consisting exclusively of an Exchange Act report or other Exchange Act filing otherwise publicly available on the Company’s website. If the Shelf Registration Statement, as amended or supplemented from time to time, ceases to be effective for any reason at any time during the Effective Period (other than because all Registrable Securities registered thereunder shall have been sold pursuant thereto or shall have otherwise ceased to be Registrable Securities), the Company shall use its reasonable best efforts to obtain the prompt withdrawal of any order suspending the effectiveness thereof.

(c) Each Holder of Registrable Securities agrees that if such Holder wishes to sell Registrable Securities pursuant to the Shelf Registration Statement and related Prospectus, it will do so only in accordance with this Section 2(c) and Section 3(b). From and after the date the Shelf Registration Statement is declared or becomes effective, the Company shall, as promptly as is practicable after the date a Notice and Questionnaire is delivered, and in any event within fifteen (15) calendar days after the date of receipt of such Notice and Questionnaire, or if the use of the Prospectus has been suspended by the Company under Section 3(b) at the time of receipt of the Notice and Questionnaire, fifteen (15) calendar days after the expiration of the period during which the use of the Prospectus is suspended:

(i) if required by applicable law, file with the Commission a post-effective amendment to the Shelf Registration Statement or prepare and, if required by applicable law, file a supplement to the related Prospectus or a supplement or amendment to any document incorporated therein by reference or file any other required document so that the Holder delivering such Notice and Questionnaire is named as a selling security holder in the Shelf Registration Statement and the related Prospectus in such a manner as to permit such Holder to deliver such Prospectus to purchasers of the Registrable Securities in accordance with applicable law and, if the Company shall file a post-effective amendment to the Shelf Registration Statement, use its reasonable best efforts to cause such post-effective amendment to be declared or to otherwise become effective under the Securities Act as promptly as is practicable. Notwithstanding the foregoing, the Company shall not be required to file more than two post-effective amendments to the Shelf Registration Statement or three supplements to the related Prospectus during any calendar quarter;

(ii) provide such Holder copies of any documents filed pursuant to Section 2(c)(i); and

(iii) notify such Holder as promptly as practicable after the effectiveness under the Securities Act of any post-effective amendment filed pursuant to Section 2(c)(i);

provided that if such Notice and Questionnaire is delivered during a Deferral Period, the Company shall so inform the Holder delivering such Notice and Questionnaire and shall take the actions set forth in clauses (i), (ii) and (iii) above upon expiration of the Deferral Period in accordance with Section 3(b). Notwithstanding anything contained herein to the contrary, the Company shall be under no obligation to name any Holder that is not a Notice Holder as a selling securityholder in any Shelf Registration Statement or related Prospectus; provided, however , that any Holder that becomes a Notice Holder pursuant to the provisions of this Section 2(c) (whether or not such Holder was a Notice Holder at the time the Shelf Registration Statement was declared or otherwise became effective) shall be named as a selling securityholder in the Shelf Registration Statement or related Prospectus in accordance with the requirements of this Section 2(c).

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(d) If any of the following events (any such event a “ Registration Default ”) shall occur, then additional interest (the “ Additional Interest ”) shall become payable by the Company to Holders in respect of the Notes as follows:

(i) if the Shelf Registration Statement is not declared effective and does not otherwise become effective within one hundred ninety (190) calendar days following the Closing Date, then commencing on the one hundred ninety-first (191 ^st ) calendar day after the Closing Date, Additional Interest shall accrue on the principal amount of the outstanding Notes that are Registrable Securities at a rate of 0.25% per annum for the first ninety (90) calendar days following such one hundred ninety-first (191 ^st ) calendar day and at a rate of 0.50% per annum thereafter; or

(ii) if the Company has failed to perform its obligations set forth in Section 2(c) within the time periods required therein, then commencing on the first day after the date by which the Company were required to perform such obligations, Additional Interest shall accrue on the principal amount of the outstanding Notes that are Registrable Securities at a rate of 0.25% per annum for the first ninety (90) calendar days and at a rate of 0.50% per annum thereafter; or

(iii) if the Shelf Registration Statement has been declared effective or has otherwise become effective but such Shelf Registration Statement ceases to be effective at any time during the Effective Period (other than pursuant to Section 3(b)), then commencing on the day such Shelf Registration Statement ceases to be effective, Additional Interest shall accrue on the principal amount of the outstanding Notes that are Registrable Securities at a rate of 0.25% per annum for the first ninety (90) calendar days following such date on which the Shelf Registration Statement ceases to be effective and at a rate of 0.50% per annum thereafter; or

(iv) if the aggregate duration of Deferral Periods in any period exceeds the number of days permitted in respect of such period pursuant to Section 3(b), then commencing on the day the aggregate duration of Deferral Periods in any period exceeds the number of days permitted in respect of such period (and again on the first day of any subsequent Deferral Period during such period), Additional Interest shall accrue on the principal amount of the outstanding Notes that are Registrable Securities at a rate of 0.25% per annum for the first ninety (90) calendar days and at a rate of 0.50% per annum thereafter;

provided, however , that the Additional Interest rate on the Notes shall not exceed in the aggregate 0.50% per annum and shall not be payable under more than one clause above for any given period of time, except that if Additional Interest would be payable under more than one clause above, but at a rate of 0.25% per annum under one clause and at a rate of 0.50% per annum under the other, then the Additional Interest rate shall be the higher rate of 0.50% per annum; provided further , however, that (1) upon the effectiveness of the Shelf Registration Statement (in the case of clause (i) above), (2) upon the performance by the Company of its obligations set forth in Section 2(c) within the time periods required therein (in the case of clause (ii) above), (3) upon the effectiveness of the Shelf Registration Statement which had ceased to remain effective (in the case of clause (iii) above), (4) upon the termination of the Deferral Period that caused the limit on the aggregate duration of Deferral Periods in a period set forth in Section 3(b) to be exceeded (in the case of clause (iv) above), (5) upon the first anniversary of the last date of original issuance of the Notes, Additional Interest on the Notes as a result of such clause, as the case may be, shall cease to accrue.

Additional Interest on the Notes, if any, will be payable in cash in accordance with the provisions of the Indenture governing the payment of interest on the Notes. Following the cure of all Registration Defaults requiring the payment of Additional Interest to the Holders of Notes that are Registrable Securities pursuant to this Section 2, the accrual of Additional Interest will

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cease (without in any way limiting the effect of any subsequent Registration Default requiring the payment of Additional Interest). Notwithstanding any provision in this Agreement, in no event shall Additional Interest accrue to Holders of Shares issued upon conversion of Notes.

The Company shall notify the Trustee immediately upon the happening of each and every Registration Default. The Trustee shall be entitled, on behalf of Holders of Securities, to seek any available remedy for the enforcement of this Agreement, including for the payment of any Additional Interest. Notwithstanding the foregoing, the parties agree that the sole monetary damages payable for a violation of the terms of this Agreement with respect to which additional monetary amounts are expressly provided shall be as set forth in this Section 2(d). Nothing shall preclude a Notice Holder or Holder of Registrable Securities from pursuing or obtaining specific performance or other equitable relief with respect to this Agreement.

(e) A Shelf Registration Statement pursuant to this Section 2 will not be deemed to have become effective unless it has been declared effective by the Commission or is automatically effective upon filing with the Commission as provided by Rule 462 under the Securities Act.

The following provisions shall apply to the Shelf Registration Statement filed pursuant to Section 2:

(a) The Company shall:

(i) prepare and file with the Commission a registration statement with respect to the shelf registration on any form which may be utilized by the Company and which shall permit the disposition of the Registrable Securities in accordance with the intended method or methods thereof, as specified in writing by the Holders of the Registrable Securities, and use its reasonable best efforts to cause such registration statement to become effective in accordance with Section 2(a) above;

(ii) before filing any Shelf Registration Statement or Prospectus or any amendments or supplements thereto with the Commission, furnish to the Initial Purchasers copies of all such documents proposed to be filed and use its reasonable best efforts to reflect in each such document when so filed with the Commission such comments as the Initial Purchasers reasonably shall propose within three (3) Business Days of the delivery of such copies to the Initial Purchasers;

(iii) use its reasonable best efforts to prepare and file with the Commission such amendments and post-effective amendments to the Shelf Registration Statement and file with the Commission any other required document as may be necessary to keep such Shelf Registration Statement continuously effective until the expiration of the Effective Period; cause the related Prospectus to be supplemented by any required prospectus supplement, and as so supplemented to be filed pursuant to Rule 424 (or any similar provisions then in force) under the Securities Act; and comply with the provisions of the Securities Act applicable to it with respect to the disposition of all Securities covered by such Shelf Registration Statement during the Effective Period in accordance with the intended methods of disposition by the sellers thereof set forth in such Shelf Registration Statement as so amended or such Prospectus as so supplemented;

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(iv) promptly notify the Notice Holders of Registrable Securities (A) when such Shelf Registration Statement or the Prospectus included therein or any amendment or supplement to the Prospectus or post-effective amendment has been filed with the Commission, and, with respect to such Shelf Registration Statement or any post-effective amendment, when the same has become effective, (B) of any request, following the effectiveness of the Shelf Registration Statement, by the Commission or any other federal or state governmental authority for amendments or supplements to the Shelf Registration Statement or related Prospectus or for additional information relating thereto, (C) of the issuance by the Commission of any stop order suspending the effectiveness of such Shelf Registration Statement or the initiation or written threat of any proceedings for that purpose, including the receipt by the Company of any notice of objection of the Commission to the use of a Shelf Registration Statement or any post-effective amendment thereto pursuant to Rule 401(g)(2) under the Securities Act, (D) of the receipt by the Company of any notification with respect to the suspension of the qualification of the Registrable Securities for sale in any jurisdiction or the initiation or written threat of any proceeding for such purpose, (E) of the determination by the Company that a post-effective amendment to the Shelf Registration Statement will be filed with the Commission, which notice may, at the discretion of the Company (or as required pursuant to Section 3(b)), state that it constitutes a Deferral Notice, in which event the provisions of Section 3(b) shall apply or (F) at any time when a Prospectus is required to be delivered under the Securities Act, that the Shelf Registration Statement, Prospectus, Prospectus amendment or supplement or post-effective amendment does not conform in all material respects to the applicable requirements of the Securities Act and the Trust Indenture Act and the rules and regulations of the Commission thereunder;

(v) prior to any public offering of the Registrable Securities pursuant to the Shelf Registration Statement, use its reasonable best efforts to register or qualify, or cooperate with the Notice Holders of Securities included therein and their respective counsel in connection with the registration or qualification of, such Securities for offer and sale under the securities or blue sky laws of such jurisdictions as any such Notice Holders reasonably requests in writing and do any and all other acts or things necessary or advisable to enable the offer and sale in such jurisdictions of the Securities covered by the Shelf Registration Statement; prior to any public offering of the Registrable Securities pursuant to the Shelf Registration Statement, use its reasonable best efforts to keep each such registration or qualification (or exemption therefrom) effective during the Effective Period in connection with such Notice Holder’s offer and sale of Registrable Securities pursuant to such registration or qualification (or exemption therefrom) and do any and all other acts or things necessary or advisable to enable the disposition in such jurisdictions of such Registrable Securities in the manner set forth in the Shelf Registration Statement and the related Prospectus; provided that the Company will not be required to qualify generally to do business in any jurisdiction where it is not then so qualified or to take any action which would subject it to general service of process or to taxation in any such jurisdiction where it is not then so subject;

(vi) use its reasonable best efforts to prevent the issuance of, and if issued, to obtain the withdrawal of any order suspending the effectiveness of the Shelf Registration Statement or, in the event of an objection of the Commission pursuant to Rule 401(g)(2), promptly file an amendment to such Shelf Registration Statement on the proper form, and to lift any suspension of the qualification of any of the Registrable Securities for sale in any jurisdiction in which they have been qualified for sale, in each case at the earliest