Exhibit 5.1

June 30, 2025

Allbirds, Inc.

30 Hotaling Place

San Francisco, CA 9411

Ladies and Gentlemen:

We have acted as counsel to Allbirds, Inc., a Delaware public benefit corporation (the “Company”), in connection with its filing on the date hereof with the Securities and Exchange Commission (the “Commission”) of a registration statement on Form S-3 (as amended, the “Registration Statement”), including a base prospectus (the “Base Prospectus”), which provides that it will be supplemented by one or more prospectus supplements (each such prospectus supplement, together with the Base Prospectus, a “Prospectus”), under the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration for issue and sale by the Company of up to $100,000,000 in aggregate offering amount of (i) shares of the Company’s common stock, $0.0001 par value per share (“Common Stock”), (ii) shares of one or more series of the Company’s preferred stock, $0.0001 par value per share (“Preferred Stock”), (iii) one or more series of the Company’s debt securities (collectively, “Debt Securities”) to be issued under an indenture to be entered into between the Company, as issuer, and a trustee (a form of which is included as Exhibit 4.6 to the Registration Statement) and one or more board resolutions, supplements thereto or officer’s certificates thereunder (such indenture, together with the applicable board resolution, supplement or officer’s certificate pertaining to the applicable series of Debt Securities, the “Applicable Indenture”), (iv) warrants to purchase Common Stock, Preferred Stock or Debt Securities (“Warrants”), and (v) units consisting of two or more of the Securities (as defined below) (“Units”). The Common Stock, Preferred Stock, Debt Securities, Warrants and Units, plus any additional Common Stock, Preferred Stock, Debt Securities, Warrants and Units that may be registered pursuant to any subsequent registration statement that the Company may hereafter file with the Commission pursuant to Rule 462(b) under the Act in connection with the offering by the Company contemplated by the Registration Statement, are referred to herein collectively as the “Securities.”

This opinion letter is furnished to you at your request to enable you to fulfill the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act in connection with the Registration Statement, and no opinion is expressed or may be implied herein as to any matter pertaining to the contents of the Registration Statement other than as to the valid issuance of the Securities.

As the basis for the opinion hereinafter expressed, we have examined such statutes, including the Delaware General Corporation Law (the “DGCL”), corporate records and

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Allbirds, Inc. June 30, 2025 Page 2

documents of the Company, certificates of officers of the Company and public officials, and other instruments and documents as we deemed relevant or necessary for the purposes of the opinion set forth below, including, but not limited to:

1. the Registration Statement, including the Prospectus;

2. the Ninth Amended and Restated Certificate of Incorporation of the Company, as filed with the Secretary of State of the State of Delaware on November 5, 2021, as amended by the Certificate of Amendment filed August 29, 2024, and certified by the Secretary of State of the State of Delaware;

3. the Amended and Restated Bylaws of the Company, effective as of August 17, 2023 (the “Bylaws”), certified by the Corporate Secretary of the Company as being in full force and effect on the date hereof; and

4. resolutions, minutes of meetings, and corporate records of actions taken by the Board of Directors of the Company (the “Board”) and committees thereof, as furnished and certified to us by the Company.

In making our examination, we have assumed (i) that all signatures on documents examined by us are genuine; (ii) the authenticity of all documents submitted to us as originals; (iii) the conformity with the original documents of all documents submitted to us as certified, conformed, electronic or photostatic copies; (iv) that each individual signing in a representative capacity (other than on behalf of the Company) any document reviewed by us had authority to sign in such capacity; (v) that each individual signing in a representative capacity any document reviewed by us had legal capacity to sign in such capacity; (vi) the truth, accuracy, and completeness of the information, representations, and warranties contained in the records, documents, instruments, and certificates we have reviewed; (vii) that the Registration Statement, Prospectus and the organizational documents of the Company, each as amended to the date hereof, will not have been amended from the date hereof in a manner that would affect the validity of the opinion rendered herein; and (viii) the accuracy, completeness and authenticity of certificates of public officials.

In connection with the opinion hereinafter expressed, we have also assumed that: (i) the Securities will be issued and sold in compliance with federal and state securities laws and in the manner stated in the Registration Statement and the Prospectus; and (ii) all corporate or other action required to be taken by the Company to duly authorize the issuance of the Securities and the terms of the offering thereof, and any related documentation (including the execution, delivery and performance of the Securities, and any related documentation referred to in our opinion set forth below) shall have been duly completed and shall remain in full force and effect.

Based on the foregoing and on such legal considerations as we deem relevant, and subject to the limitations, qualifications, exceptions, and assumptions set forth herein and in reliance on the statements of fact contained in the documents we have examined, we are of the opinion that:

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1. When an issuance of Common Stock has been duly authorized by all necessary corporate action of the Company, upon issuance, delivery and payment therefor in an amount not less than the par value thereof in the manner contemplated by the applicable Prospectus and by such corporate action, and in total amounts and numbers of shares that do not exceed the respective total amounts and numbers of shares (a) available under the certificate of incorporation, and (b) authorized by the board of directors in connection with the offering contemplated by the applicable Prospectus, such shares of Common Stock will be validly issued, fully paid and nonassessable. In rendering the foregoing opinion, we have assumed that the Company will comply with all applicable notice requirements regarding uncertificated shares provided in the DGCL.

2. When an issuance of Preferred Stock has been duly authorized by all necessary corporate action of the Company, upon issuance, delivery and payment therefor in an amount not less than the par value thereof in the manner contemplated by the applicable Prospectus and by such corporate action, and in total amounts and numbers of shares that do not exceed the respective total amounts and numbers of shares (a) available under the certificate of incorporation, and (b) authorized by the board of directors in connection with the offering contemplated by the applicable Prospectus, such shares of Preferred Stock will be validly issued, fully paid and nonassessable. In rendering the foregoing opinion, we have assumed that the Company will comply with all applicable notice requirements regarding uncertificated shares provided in the DGCL.

3. When the Applicable Indenture has been duly authorized, executed and delivered by all necessary corporate action of the Company, and when the specific terms of a particular series of Debt Securities have been duly established in accordance with the terms of the Applicable Indenture and authorized by all necessary corporate action of the Company, and such Debt Securities have been duly executed, authenticated, issued and delivered against payment therefor in accordance with the terms of the Applicable Indenture and in the manner contemplated by the applicable Prospectus and by such corporate action, such Debt Securities will be the legally valid and binding obligations of the Company, enforceable against the Company in accordance with their terms.

4. When the applicable warrant agreement has been duly authorized, executed and delivered by all necessary corporate action of the Company, and when the specific terms of a particular issuance of Warrants have been duly established in accordance with the terms of the applicable warrant agreement and authorized by all necessary corporate action of the Company, and such Warrants have been duly executed, authenticated, issued and delivered against payment therefor in accordance with the terms of the applicable warrant agreement and in the manner contemplated by the applicable Prospectus and by such corporate action (assuming the securities issuable upon exercise of such Warrants have been duly authorized and reserved for issuance by all necessary corporate action), such Warrants will be the legally valid and binding obligations of the Company, enforceable against the Company in accordance with their terms.

5. When the applicable unit agreement has been duly authorized, executed and delivered by all necessary corporate action of the Company, and when the specific terms of a particular issuance of Units have been duly authorized in accordance with the terms of the applicable unit agreement and authorized by all necessary corporate action of the Company, and

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such Units have been duly executed, authenticated, issued and delivered against payment therefor in accordance with the terms of the applicable unit agreement and in the manner contemplated by the applicable Prospectus and by such corporate action (assuming the securities issuable upon exercise of such Units have been duly authorized and reserved for issuance by all necessary corporate action), such Units will be the legally valid and binding obligations of the Company, enforceable against the Company in accordance with their terms.

Our opinion set forth herein is subject to and limited by the effect of (i) the effect of bankruptcy, insolvency, reorganization, preference, fraudulent transfer, moratorium or other similar laws relating to or affecting the rights and remedies of creditors; (ii) (a) the effect of general principles of equity, whether considered in a proceeding in equity or at law (including the possible unavailability of specific performance or injunctive relief), (b) concepts of materiality, reasonableness, good faith and fair dealing, and (c) the discretion of the court before which a proceeding is brought; and (iii) the invalidity under certain circumstances under law or court decisions of provisions providing for the indemnification of or contribution to a party with respect to a liability where such indemnification or contribution is contrary to public policy. We express no opinion as to (a) any provision for liquidated damages, default interest, late charges, monetary penalties, make-whole premiums or other economic remedies to the extent such provisions are deemed to constitute a penalty, (b) consents to, or restrictions upon, governing law, jurisdiction, venue, arbitration, remedies, or judicial relief, (c) waivers of rights or defenses, (d) any provision requiring the payment of attorneys’ fees, where such payment is contrary to law or public policy, (e) any provision permitting, upon acceleration of any Debt Securities, collection of that portion of the stated principal amount thereof which might be determined to constitute unearned interest thereon, (f) the creation, validity, attachment, perfection, or priority of any lien or security interest, (g) advance waivers of claims, defenses, rights granted by law, or notice, opportunity for hearing, evidentiary requirements, statutes of limitation, trial by jury or at law, or other procedural rights, (h) waivers of broadly or vaguely stated rights, (i) provisions for exclusivity, election or cumulation of rights or remedies, (j) provisions authorizing or validating conclusive or discretionary determinations, (k) grants of setoff rights, (l) proxies, powers and trusts, (m) provisions prohibiting, restricting, or requiring consent to assignment or transfer of any right or property, (n) any provision to the extent it requires that a claim with respect to a security denominated in other than U.S. dollars (or a judgment in respect of such a claim) be converted into U.S. dollars at a rate of exchange at a particular date, to the extent applicable law otherwise provides, and (o) the severability, if invalid, of provisions to the foregoing effect.

The opinion expressed herein is limited solely and in all respects to the DGCL and the federal laws of the United States of America that, in our experience, are applicable to transactions of the type contemplated by the Sales Agreement, and we express no opinion as to the laws of any other jurisdiction. We express no opinion as to any matter other than as expressly set forth above, and no other opinion is intended to be implied or inferred herefrom. The opinion expressed herein is given as of the date hereof and we undertake no obligation hereby and disclaim any obligation to advise you of any change in law, facts or circumstances occurring after the date hereof pertaining to any matter referred to herein.

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This opinion is provided as a legal opinion only, effective as of the date of this letter, and not as representations of fact. We understand that you have made such independent investigations of the facts as you deemed necessary, and that the determination of the extent of those investigations that are necessary has been made independent of this opinion letter.

We hereby consent to the reference to our firm under the caption “Legal Matters” in the Prospectus Supplement and to the filing of this opinion letter as Exhibit 5.1 to the Company’s Registration Statement on Form S-3 filed on June 30, 2025. In giving this consent, we do not admit that we are included in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission promulgated thereunder.

Very truly yours,

/s/ Holland & Hart LLP