UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16 OR 15D-16 OF THE

SECURITIES EXCHANGE ACT OF 1934

For the month of December 2023

Commission File Number: 001-41889

CADELER A/S

(Translation of registrant's name into English)

Arne Jacobsens Allé 7, 7th floor

DK-2300 Copenhagen S, Denmark

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F x Form 40-F o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): o.

INFORMATION CONTAINED IN THIS FORM 6-K REPORT

On December 19, 2023, Cadeler A/S (the “Company”) issued stock exchange announcements announcing that it has received major shareholder notifications regarding direct and indirect holdings of shares in the Company. Copies of the stock exchange announcements are attached hereto as Exhibits 99.1 and 99.2.

Exhibit List

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.