Canadian Solar (CSIQ) 6-KRecurrent Energy Closes $513 Million in Financing for 1,200 MWh Energy Storage Project in Arizona

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 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of June 2024

Commission File Number: 001-33107

CANADIAN SOLAR INC.

545 Speedvale Avenue West, Guelph,

Ontario, Canada N1K 1E6

(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 þ  Form 40-F o

CANADIAN SOLAR INC.

Form 6-K

TABLE OF CONTENTS

SIGNATURE

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.

Date: June 20, 2024

EXHIBIT INDEX

Exhibit 99.1 — Recurrent Energy Closes $513 Million in Financing for 1,200 MWh Energy Storage Project in Arizona