As filed with the U.S. Securities and Exchange Commission on May 11, 2026

File No. 333-271700

File No. 811-23872

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

Themes ETF Trust

(Exact Name of Registrant as Specified in Charter)

34 East Putnam Avenue, Suite 112

Greenwich, CT 06830

(Address of Principal Executive Offices, Zip Code)

(646) 206-1788

(Registrant’s Telephone Number, including Area Code)

Jose C. Gonzalez

34 East Putnam Avenue, Suite 112

Greenwich, CT 06830

(Name and Address of Agent for Service)

Copy to:

Karen Aspinall, Esq.

Practus, LLP

11300 Tomahawk Creek Parkway, Suite 310

Leawood, Kansas 66211

Karen.Aspinall@Practus.com

It is proposed that this filing will become effective (check appropriate box):

If appropriate, check the following box

EXPLANATORY NOTE

This Post-Effective Amendment No. 198 under the Securities Act of 1933, as amended and Amendment No. 200 under the Investment Company Act of 1940, as amended, for the Themes ETF Trust is filed to correct the amendment numbers contained in the 485BXT submission filed on May 11, 2026 (Accession number: 0001829126-26-004884) (the “Prior Filing”). This 485BXT supersedes the Prior Filing.

The sole purpose of this filing is to delay the effectiveness of Post-Effective Amendment No. 130 (the “Amendment”) to the Registrant’s Registration Statement (filed on February 25, 2026) with respect to 21 of its proposed series (Leverage Shares 5X Long 20+ Treasury Daily ETF, Leverage Shares 5X Long Aerospace & Defense Daily ETF, Leverage Shares 5X Long Artificial Intelligence Daily ETF, Leverage Shares 5X Long China Daily ETF, Leverage Shares 5X Long China Technology Daily ETF, Leverage Shares 5X Long Developed Markets Daily ETF, Leverage Shares 5X Long Emerging Markets Daily ETF, Leverage Shares 5X Long Financials Daily ETF, Leverage Shares 5X Long Gold Miners Daily ETF, Leverage Shares 5X Long Homebuilders Daily ETF, Leverage Shares 5X Long India Daily ETF, Leverage Shares 5X Long Junior Gold Miners Daily ETF, Leverage Shares 5X Long Magnificent 7 Daily ETF, Leverage Shares 5X Long Quantum Computing Daily ETF, Leverage Shares 5X Long Regional Banks Daily ETF, Leverage Shares 5X Long Semiconductors Daily ETF, Leverage Shares 5X Long Uranium Daily ETF, Leverage Shares 5X Long US Large Cap 500 Daily ETF, Leverage Shares 5X Long US Small Cap 2000 Daily ETF, Leverage Shares 5X Long US Growth 100 Daily ETF, and Leverage Shares 5X Long World Stock Daily ETF) until June 8, 2026. Parts A and B of the Amendment are incorporated by reference herein. This amendment also incorporates by reference the information contained in Part C of Post-Effective Amendment No. 195 to the Registrant’s Registration Statement, which was filed on May 8, 2026.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 (the “Securities Act”) and the Investment Company Act of 1940, the Trust certifies that it meets all of the requirements for effectiveness of this Post-Effective Amendment to its Registration Statement on Form N-1A under Rule 485(b) under the Securities Act and has duly caused this Post-Effective Amendment No. 198 to the Registrant’s Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Greenwich, State of Connecticut, on this 11^th day of May, 2026.

Pursuant to the requirements of the Securities Act, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

Attorney-in-Fact pursuant to Powers of Attorney previously filed with Pre-Effective Amendment No. 2 to the Registrant’s registration statement on November 9, 2023