TCG İzmit Begins Sea Trials as Third İstif-Class Frigate

The Turkish Navy’s third İstif-class frigate, TCG İzmit (F-517), began sea acceptance trials on September 15, moving another hull of Türkiye’s national frigate programme into the water-testing phase at the same time two sister ships are already in service or under trial.

İzmit is being built at Sedef Shipyard in Istanbul under a January 2023 agreement between state shipbuilder STM and the TAIS industrial consortium, the arrangement Türkiye uses to build İstif-class hulls in parallel at multiple private yards rather than sequentially at a single state facility. The ship was launched on January 11, 2025, and has since completed roughly 20 months of outfitting — fitting out combat systems, sensors and propulsion before contractor and Navy crews take it to sea for acceptance testing. Under its contract, İzmit is due to join the Turkish Naval Forces inventory sometime in 2026 or 2027.

Third of Class, Seventh MİLGEM Hull

İzmit is the third ship of the İstif class, also referred to as the I-class or MİLGEM II, which followed the four Ada-class corvettes that opened Türkiye’s MİLGEM programme in the 2000s. Counting the Ada corvettes, İzmit is the seventh hull to come out of the broader MİLGEM family — a lineage the MİLGEM I-Class Frigate programme traces from a 1990s-era corvette design study to a class Türkiye now builds simultaneously at four private shipyards.

Lead ship TCG İstanbul (F-515) was built at Istanbul Naval Shipyard and commissioned in January 2024. Second-of-class TCG İzmir (F-516), built at Anadolu Shipyard, began its own sea acceptance trials on August 10 this year. Two more hulls, TCG İçel (F-518) and TCG Akdeniz (F-519), have already been launched at Sefine and Anadolu shipyards respectively, and TCG Karadeniz (F-520) — built at Sedef alongside İzmit — was launched in late July. STM has also been showing the class to potential customers on the sidelines of European defence expos this month, taking the İstif-class design to three continents alongside its KARGU drones. With İzmit’s trials starting, Türkiye now has frigates from the class simultaneously in sea testing, fitting-out and delivery preparation across four yards, a pace the country has not previously sustained on a single surface combatant class.

Why It Matters Beyond Türkiye

The İstif class carries a domestic content ratio Turkish officials put above 80 percent, spanning the MİLDAR search radar family, the GENESIS combat management system and the MİDLAS vertical launch system built around ASELSAN and Roketsan-supplied interceptors. Later hulls in the class carry a strike-length MİDLAS configuration capable of housing longer munitions, including extended-range members of the SİPER air-defence interceptor family, giving the class a genuine area air-defence role rather than the point-defence fit typical of a corvette-sized combatant.

That combination of size, indigenous content and export cost has already drawn interest abroad. Türkiye’s earlier Ada-class corvette design was licence-built for Pakistan as the Babur class, and Turkish shipyards have marketed the follow-on İstif design to Gulf and South Asian navies looking for a NATO-standard frigate without the price tag or export restrictions attached to Western yards — a pitch that fits a broader pattern of NATO members already buying into Turkish-built systems. A serial-production programme running across four shipyards simultaneously is also a data point for any customer weighing whether Türkiye can deliver hulls on a compressed timeline — something STM and the Defence Industry Agency have been keen to demonstrate as the class moves from a single lead ship to a small fleet, and it sits alongside heavier programmes such as the planned TF-2000 air-defence destroyer in Türkiye’s wider surface-fleet build-out.

What Comes Next

Sea acceptance trials typically run several months and cover propulsion, seakeeping, combat-system integration and weapons firings before a ship is handed to the Navy. With İzmir several weeks ahead of İzmit in the same process, the Turkish Navy could receive its second and third İstif-class frigates in relatively close succession, depending on how each ship’s trials programme runs. Türkiye’s Defence Industry Agency has not published a specific handover date for either ship beyond the 2026–2027 window in İzmit’s original contract.

Sources: SavunmaSanayiST, Naval News.