Exhibit 5.1

Simpson Thacher & Bartlett llp

425 lexington avenue

new york, ny 10017-3954

telephone: +1-212-455-2000

facsimile: +1-212-455-2502

August 8, 2025

United Parks & Resorts Inc.
6240 Sea Harbor Drive
Orlando, Florida 32821

Ladies and Gentlemen:

We have acted as counsel to United Parks & Resorts Inc., a Delaware corporation (the “Company”), in connection with Post-Effective Amendment No. 2 (the “Amendment”) to the Registration Statement on Form S-8 (Registration No. 333-188010), previously amended by Post-Effective Amendment No. 1 on Form S-8 (as amended, the “Registration Statement”) filed by the Company with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”).

Beijing Boston Brussels HONG KONG Houston London Los Angeles luxembourg Palo Alto SÃO PAULO TOKYO Washington, D.C.

The Registration Statement registered 15,000,000 shares of common stock, par value $0.01 per share, of the Company (the “Common Stock”), reserved for issuance under the SeaWorld Entertainment, Inc. 2013 Omnibus Incentive Plan (the “2013 Plan”). Post-Effective Amendment No. 1 reflected that 7,079,237 shares of Common Stock, which were previously available for issuance under the 2013 Plan, became available for issuance under the SeaWorld Entertainment, Inc. 2017 Omnibus Incentive Plan (the “2017 Plan”), plus the number of shares of Common Stock underlying any award granted under the 2013 Plan that expired, terminated or was canceled or forfeited for any reason whatsoever under the terms of the 2013 Plan.

The Amendment reflects that a portion of the shares of Common Stock registered under the Registration Statement (6,320,680 shares of Common Stock, which were previously available for issuance under the 2017 Plan, plus the number of shares of Common Stock underlying any award granted under the 2017 Plan that expires, terminates or is canceled or forfeited for any reason whatsoever under the terms of the 2017 Plan) will become available for issuance under the Company’s 2025 Omnibus Incentive Plan, as approved by the Company’s shareholders on June 13, 2025 (the “2025 Plan”), pursuant to the terms of the 2025 Plan (such shares of Common Stock are referred to herein as the “Carryover Shares”).

We have examined the Amendment, the Amended and Restated Certificate of Incorporation of the Company and the 2025 Plan, each of which has been filed with the Commission as an exhibit to the Amendment. In addition, we have examined, and have relied as to matters of fact upon, originals, or duplicates or certified or conformed copies, of such records, agreements, documents and other instruments and such certificates or comparable documents of public officials and of officers and representatives of the Company and have made such other

investigations as we have deemed relevant and necessary in connection with the opinions hereinafter set forth.

In rendering the opinion set forth below, we have assumed the genuineness of all signatures, including electronic signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as duplicates or certified or conformed copies and the authenticity of the originals of such latter documents.

Based upon the foregoing, and subject to the qualifications, assumptions and limitations stated herein, we are of the opinion that (1) when the Board of Directors of the Company (or a duly authorized committee thereof) has taken all necessary corporate action to authorize and approve the issuance of the Carryover Shares and (2) upon issuance and delivery in accordance with the 2025 Plan, the Carryover Shares will be validly issued, fully paid and nonassessable.

We do not express any opinion herein concerning any law other than the Delaware General Corporation Law.

We hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Amendment.

Very truly yours,

/s/ Simpson Thacher & Bartlett LLP

SIMPSON THACHER & BARTLETT LLP