Turkcell Iletisim Hizmetleri A S

UNDER THE SECURITIES EXCHANGE ACT OF 1934

TURKCELL İLETİŞİM HİZMETLERİ A.Ş.

(Translation of registrant's name into English)

Turkcell Küçükyalı Plaza

Aydınevler Mahallesi, İsmet İnönü Caddesi, No:20

Küçükyalı B Blok Ofispark

(Address of Principal Executive Offices)

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

Enclosure: A press release dated September 24, 2026 announcing the registrant's decision to issue Lease Certificates.

Announcement Regarding the Decisions to Issue Lease Certificates

Our Company's Board of Directors also resolved that our wholly-owned subsidiary Turkcell Finansman A.Ş. may issue management agreement-based lease certificates (sukuk), in accordance with capital markets legislation, through an asset leasing company based in Türkiye, at an amount of up to TRY 6 billion, with maturities up to 12 months, in the domestic market, in one or more tranches, without a public offering, as a private placement and/or to be sold to institutional investors. The respective issuances are subject to the approval of the Capital Markets Board.

This press release does not constitute an offer to sell, or a solicitation of offers to purchase or subscribe for, securities in the United States or any other jurisdiction in which such offer or solicitation would be unlawful. The securities referred to herein have not been and will not be registered under the U.S. Securities Act of 1933, as amended (the "Securities Act"), and may not be offered, sold or delivered within the United States or to or for the benefit of, US persons (as defined in Regulation S under the Securities Act) absent registration or an applicable exemption from the registration requirements of the Securities Act. This press release is being issued pursuant to and in accordance with Rule 135c under the Securities Act.