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 October 9, 2026 announcing the registrant's financing bond issuance.

Announcement Regarding the Financing Bond Issuance

Within the scope of the TRY 15,000,000,000 issuance limit approved by the Capital Markets Board, the book building of the financing bond issuance of our Company with a maturity date of January 8, 2027, an annual simple interest of 37.00% with a nominal amount of TRY 500,000,000 to qualified investors within Türkiye, without a public placement was completed, and the securities will be transferred to the investor accounts on October 9, 2026 (today).

Issue Limit Security Type : Debt Securities

Sale Type : Private Placement-Sale to Qualified Investor

Capital Market Board Approval Date : 17.06.2026

Capital Market Instrument to be Issued Info

The country where the issue takes place : Türkiye

Central Securities Depository : Merkezi Kayıt Kuruluşu A.Ş.

Nominal Value of Capital Market Instrument Sold : 500,000,000

Interest Rate - Yearly Simple (%) : 37.0000

Interest Rate - Yearly Compound (%) : 42.4638

Coupon Payment Frequency : Single Coupon

Redemption Plan of Capital Market Instrument Sold

Coupon Number Payment Date Record Date* Payment Date Interest Rate -

* The date on which the beneficiaries are determined.

Rating Company Rating Note Rating Date Is it Investment Grade?

JCR AVRASYA DERECELENDİRME A.Ş. (TR) J1+ Short Term (national) (TR) AAA Long Term (national) 22.05.2026 Yes

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.