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

Forthe month of August 2025

Commission File Number: 001-38313

Amber International Holding Limited

(Registrant’sname)

1 Wallich Street, #30-02 Guoco Tower, Singapore078881

Tel:+65 60220228

(Address of principal executive office)

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

Form20-F  x   Form 40-F  ¨

AmberInternational Holding Limited Announces Appointment of New Director

AmberInternational Holding Limited (the “Company” or “Amber International”) today announced the appointment of Mr.Lin Ma (“Mr. Ma”) as a new director of the Company’s board of directors (the “Board”), effective August1, 2025. Mr. Ma will also serve as a new member of the compensation committee, corporate governance and nominating committee, and investmentcommittee of the Board.

Mr. Ma has extensive experience in strategic transactions,merger and acquisition, and corporate legal affairs. Since March 2025, he is Co-Chief Operating Officer & Managing Partner of AmberGlobal Limited (“Amber Group”), a leading provider of global crypto financial services, and Amber International’s shareholderand strategic partner. With expertise in operational strategy, transaction management and regulatory compliance, Mr. Ma plays an activerole in board-level decision-making and investor relations, which drives Amber Group’s growth and oversees strategic partnershipsworldwide.

Previously, Mr. Ma served as Chief Legal Officerfrom 2023 and Head of Strategic Transactions of Amber Group from 2021 to 2023, where he drove strategic transactions that shaped AmberGroup's global footprint, including the Nasdaq listing of Amber International, the sale of Amber Japan to Sony Group, and acquisitionsof Sparrow Tech and DeCurret Inc. He also led high-value funding rounds and equity investments, reinforcing Amber Group's leadership indigital asset infrastructure.

Prior to joining Amber Group, Mr. Ma brought overalmost a decade of prior legal and advisory experience from leading international law firms, where he worked alongside corporate boardsand investment committees to deliver complex M&A transactions globally across Asia, Australia, Europe, and North America.

Mr. Ma received Juris Doctor degree from ColumbiaLaw School and is admitted to practice in New York and Australia.

“Weare delighted to welcome Mr. Ma to the Board. His professional knowledge and experience makes him a strong addition to our Board as wepursue the Company's expansion and cement its leadership at the intersection of traditional and decentralized finance. We look forwardto leveraging his insights to drive our strategy forward.” said Wayne Huo, Chief Executive Officer of Amber International.

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.

Date:August 1, 2025