The Istanbul-class frigate (also referred to as the İstif-class under Türkiye’s MİLGEM (Milli Gemi – “National Ship”) programme) is a modern, multirole surface combatant developed to replace older Yavuz-class frigates and expand Turkey’s blue-water naval capabilities. It is an enlarged and more capable evolution of the Ada-class corvette, with a length of about 113 m, a beam of ~14.4 m, and a displacement in the ~3,000–3,150 ton range. The design features a CODAG (combined diesel and gas) propulsion system for speeds above 29 knots and a range of roughly 5,700 nmi at cruising speed. Armament and sensors are predominantly indigenously developed and integrated, including Roketsan Atmaca anti-ship missiles, a MİDLAS vertical-launch system with HISAR surface-to-air capability, Aselsan Gökdeniz CIWS, advanced AESA radar and EW suites, and a modern combat management system by HAVELSAN. The class also incorporates anti-submarine warfare sensors and weapons, a helicopter hangar/flight deck, and other systems for full-spectrum maritime operations.Recent updates to the MİLGEM programme include ongoing construction and outfitting of multiple Istanbul-class hulls across Turkish shipyards under the TAIS–STM partnership, with the lead ship TCG İstanbul (F-515) commissioned in January 2024 and several sister ships launched or nearing completion as part of an expanded eight-ship programme.Significantly, the Istanbul class has begun to enter the export market. In July 2025 Indonesia signed a contract with Türkiye’s TAIS to acquire two Istanbul-class frigates—the first export order for the type—and the acquisition is reportedly structured with financing support via a Barzan Holdings framework. These vessels were originally intended for the Turkish Navy (e.g., planned TCG İzmir and TCG İçel) but will be transferred to the Indonesian Navy as part of the deal, marking a milestone in Turkish naval exports.