Exhibit 5.1

	609 Main Street Houston, TX 77002 United States
		Facsimile:
	+1 713 836 3600	+1 713 836 3601

	www.kirkland.com

September 23, 2025

Rice Acquisition Corporation 3

102 East Main Street

Second Story Carnegie, PA 15106

Re:

Rice Acquisition Corporation 3 Registration Statement on Form S-1

Ladies and Gentlemen:

We are issuing this opinion in our capacity as special United States counsel to Rice Acquisition Corporation 3, a Cayman Islands exempted company (the “Company”), in connection with the registration under the Securities Act of 1933, as amended (the “Act”), on a Registration Statement on Form S-1, initially publicly filed with the U.S. Securities and Exchange Commission (the “Commission”) on August 29, 2025 (such Registration Statement, as amended at the effective date thereof, being referred to herein as the “Registration Statement”) of 34,500,000 units of the Company, including the underwriter’s over-allotment option to purchase up to an additional 4,500,000 units (collectively, the “Units”), with each Unit consisting of one Class A ordinary share, par value $0.0001 per share (the “Class A Ordinary Shares”), of the Company and one-sixth of one redeemable warrant of the Company to purchase one Class A Ordinary Share (the “Warrants”).

This opinion is being furnished in accordance with the requirements of Item 601(b)(5) of Regulation S-K promulgated under the Act. In rendering the opinions stated herein, we have examined and relied upon the following:

(a) the form of Underwriting Agreement (the “Underwriting Agreement”) proposed to be entered into by and among the Company, Rice Acquisition Holdings 3 LLC, a Cayman Islands limited liability company, and Barclays Capital Inc. and Jefferies LLC, as representatives of the several underwriters named therein (the “Underwriters”), relating to the sale by the Company to the Underwriters of the Units, filed as Exhibit 1.1 to the Registration Statement;

(b) the form of Unit Certificate, filed as Exhibit 4.1 to the Registration Statement;

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Rice Acquisition Corporation 3

September 23, 2025

Page 2

(d) the form of Warrant Agreement proposed to be entered into by and between the Company and Odyssey Transfer and Trust Company, as warrant agent (the “Warrant Agreement”), filed as Exhibit 4.4 to the Registration Statement.

For purposes of this letter, we have examined such other documents, records, certificates, resolutions and other instruments deemed necessary as a basis for this opinion, and we have assumed the authenticity of all documents submitted to us as originals, the conformity to the originals of all documents submitted to us as copies and the authenticity of the originals of all documents submitted to us as copies. As to any facts material to the opinions expressed herein which we have not independently established or verified, we have relied upon statements and representations of officers and other representatives of the Company and others.

We do not express any opinion with respect to the laws of any jurisdiction other than the laws of the State of New York.

Based upon the foregoing and subject to the qualifications and assumptions stated herein, we are of the opinion that:

1. When the Units are delivered in accordance with the Underwriting Agreement upon payment of the agreed upon consideration therefor, the Units will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms under the laws of the State of New York.

Rice Acquisition Corporation 3

September 23, 2025

Page 3

2. When the Units are delivered in accordance with the Underwriting Agreement upon payment of the agreed upon consideration therefor, the Warrants included in such Units will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms under the laws of the State of New York.

Our opinions expressed above are subject to the qualifications that we express no opinion as to the applicability of, compliance with, or effect of (i) any bankruptcy, insolvency, reorganization, fraudulent transfer, fraudulent conveyance, moratorium or other similar law or judicially developed doctrine in this area (such as substantive consolidation or equitable subordination) affecting the enforcement of creditors’ rights generally, (ii) general principles of equity (regardless of whether enforcement is considered in a proceeding in equity or at law), (iii) an implied covenant of good faith and fair dealing, (iv) public policy considerations which may limit the rights of parties to obtain certain remedies, (v) any requirement that a claim with respect to any security denominated in other than U.S. dollars (or a judgment denominated in other than U.S. dollars in respect of such claim) be converted into U.S. dollars at a rate of exchange prevailing on a date determined in accordance with applicable law, (vi) governmental authority to limit, delay or prohibit the making of payments outside of the United States or in a foreign currency or currency unit and (vii) any laws except the laws of the State of New York. We advise you that issues addressed by this letter may be governed in whole or in part by other laws, but we express no opinion as to whether any relevant difference exists between the laws upon which our opinions are based and any other laws which may actually govern.

Rice Acquisition Corporation 3

September 23, 2025

Page 4

We hereby consent to the filing of this opinion with the Commission as Exhibit 5.1 to the Registration Statement. We also consent to the reference to our firm under the heading “Legal Matters” in the Registration Statement. In giving this consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission.

We do not find it necessary for the purposes of this opinion, and accordingly we do not purport to cover herein, the application of the securities or “Blue Sky” laws of the various states to the offering of the Units.

This opinion is limited to the specific issues addressed herein, and no opinion may be inferred or implied beyond that expressly stated herein. We assume no obligation to revise or supplement this opinion should the present laws of the State of New York be changed by legislative action, judicial decision or otherwise.

This opinion is furnished to you in connection with the filing of the Registration Statement and is not to be used, circulated, quoted or otherwise relied upon for any other purposes.

	Very truly yours,

	/s/ KIRKLAND & ELLIS LLP

Rice Acquisition Corp 3 S-1/A