US Navy eyes three foreign frigate designs to rapidly match China's growing production rates.

On September 1, 2026, the U.S. Navy initiated formal evaluations of three foreign frigate designs (Japan’s Mogami-class, South Korea’s Chungnam-class, and Türkiye’s Istanbul-class) to rapidly restore surface fleet capacity following the truncation of the domestic Constellation-class program. The foreign procurement framework allocates $1.85 billion in FY2027 funds to acquire up to two overseas-built lead ships before transferring construction and manufacturing processes to American shipyards from hull 3 onward. This strategy aims to bypass domestic shipbuilding delays and establish serial production to counter the rapid numerical expansion of China's surface fleet.

The U.S. Navy's international assessment evaluates Japan's 5,500-ton Mogami-class, South Korea's 4,300-ton Chungnam-class, and Türkiye's 3,100-ton Istanbul-class for a foreign-to-domestic technology transfer model. Under the August 13, 2026 framework, selected contractors must acquire or build U.S. shipyard capacity, with an initial assessment deadline set for November 12, 2026.

Related topic: Brazil confirms talks with U.S. Air Force to use KC-390 Millennium as a new complementary tanker

The three foreign frigate designs being considered by the U.S. Navy are Türkiye’s Istanbul-class (top left), South Korea’s Chungnam-class (top right), and Japan’s Mogami-class (bottom left), and would complement the domestically built FF(X) program (bottom right). (Picture source: STM, X/mason_8718, Japan MoD, US DoD)

On September 1, 2026, USNI News reported that the U.S. Navy was evaluating three allied frigate families for a procurement path intended to restore a conventional frigate force faster than a new clean-sheet American design: Japan’s Mogami-class, South Korea’s Chungnam-class FFX Batch III, and Türkiye’s Istanbul-class. The concept would allow no more than the first two U.S. ships to be built at the selected foreign yard before construction transfers to the United States from hull 3 onward. The FY2027 proposal allocated $1.85 billion to the foreign warship effort, initially focused on Japan and South Korea before Türkiye entered consideration, and the U.S. Navy’s international assessment is due on November 12, 2026.

The foreign frigate track is separate from the National Security Cutter-derived FF(X), for which Ingalls Shipbuilding has already started preproduction work but has not received a construction award, and it follows the truncation of the Constellation-class program after that FREMM-derived design grew beyond 7,800 tons. The Istanbul-class, for its part, displaces roughly 3,100 tons and measures 113.2 m; the Chungnam-class reaches 4,300 tons full load and roughly 130 m; the Mogami-class reaches roughly 5,500 tons and 133 m. The procurement decision is therefore a test of whether the U.S. Navy can finally select a ship already being built in serial production, limit U.S.-specific redesign, transfer the manufacturing system to an American yard, and sustain a useful delivery rate before the Chinese frigate inventory grows significantly further. 

Under the August 13, 2026 acquisition framework, the selected company would have to construct a new American shipyard, acquire an existing one or take majority ownership of a U.S. yard, then transfer production methods, train American workers, license proprietary manufacturing technologies and establish a U.S.-based construction and maintenance supply chain. The model follows the Coast Guard icebreaker arrangement under which four initial ships would be constructed in Finland and seven in the United States, but the frigate requirement is more complex because a modern combatant combines hull fabrication with combat systems, radars, VLS installation, electronic warfare, aviation facilities and much tighter shock, signature and survivability requirements. Congressional approval also remains uncertain.

Senate Armed Services Committee draft FY2027 language would remove the foreign-construction waiver, while House Armed Services Committee language would prevent authorized funds from purchasing a U.S. warship built overseas. Even if Congress permits the first two foreign-built ships, the decisive schedule is not hull 1. Hull 3 is the real test because the American yard must reproduce the foreign builder’s block construction sequence, tolerances, welding procedures, outfitting order, cable installation, supplier timing, and quality-control system while simultaneously qualifying a new workforce. Congress would therefore need to track the foreign hull 1 delivery date, hull 2 delivery date, start of U.S. hull 3, launch and delivery of hull 3, interval between hulls 3 and 4, and annual output after localization.

Japan’s Mogami-class provides the largest hull and the lowest-manning architecture of the three candidates, but it also enters the U.S. competition with a heavily committed production line. The Mogami-class reaches roughly 5,500 tons full load, 133 m in length and 16.3 m in beam, versus 4,300 tons and roughly 130 m for the Chungnam and 3,100 tons and 113.2 m for the Istanbul. That additional displacement matters because Americanization consumes volume and weight margin very quickly, as seen on the Constellation. Additional U.S. communications equipment, cryptographic hardware, electronic warfare systems, cooling machinery, larger antennas, different VLS equipment, and additional accommodation can move hundreds of tons through a design while also changing electrical demand, center of gravity, and topside stability. Japan’s automation approach is equally significant.

A frigate requiring roughly 90 sailors instead of 125 saves 35 shipboard billets per hull; across 20 ships that is 700 billets before training commands, relief crews and shore support are included. Japan has already demonstrated a serial Mogami production rhythm of roughly two ships annually across the original 12-ship program, centered principally on Mitsubishi Heavy Industries at Nagasaki and the Tamano yard. Japan is now moving directly into 12 larger New FFM or Upgraded Mogami ships, with construction beginning in 2025, the first two launches planned by 2027 and all 12 JMSDF ships scheduled for delivery by 2033. That schedule requires an average production rate in the 2-3 ship-per-year range through the main delivery period. Australia selected this larger version on August 5, 2025, and the first Australian hull is scheduled for delivery in December 2029.

Japan therefore already has 15 Upgraded Mogamis committed to Japanese construction, consisting of 12 for the JMSDF and three for Australia, before any U.S. ship is inserted into the production schedule. New Zealand narrowed its Anzac replacement competition on May 7, 2026, to the Upgraded Mogami and Type 31, while Japan offered the design to Indonesia in May 2026. For the U.S. Navy, Japan offers the most mature example of the exact industrial model Washington is considering, because Australia is already requiring Japanese-built lead ships followed by domestic construction. The corresponding risk is yard saturation: U.S. hulls would compete for design, supplier, and production capacity with 12 Japanese ships and three Australian ships before American localization even begins. South Korea’s Chungnam-class presents a smaller hull than the Mogami but a more distributed shipbuilding base and recent construction intervals that can be measured ship by ship.

The FFX Batch III measures roughly 129-130 m long, 14.8 m wide and 4.2 m in draft, displaces 3,600 tons light and about 4,300 tons full load, reaches 30 knots and has a range of roughly 4,500 nmi at economical speed. Its CODLOG propulsion system combines one Rolls-Royce MT30 gas turbine, four MTU 12V 4000 M43B diesel generators, and two Leonardo DRS permanent-magnet electric motors driving two shafts. That configuration gives the class an electric operating mode useful for reducing machinery noise during anti-submarine operations, which matters because the U.S. Navy lost much of its dedicated surface ASW capacity when the Oliver Hazard Perry-class frigates retired and had intended Constellation to restore part of that role. South Korea’s strongest measurable industrial advantage is that the six Batch III ships are distributed across HD Hyundai Heavy Industries, SK Oceanplant, and Hanwha Ocean rather than concentrated at one frigate yard.

FFG-828 was laid down on April 25, 2022, and delivered on December 18, 2024, a roughly 32-month keel-to-delivery interval. FFG-829 was laid down on April 1, 2024, and delivered on June 19, 2026, reducing that interval to roughly 26 months. Hanwha Ocean then laid FFG-833 on January 27, 2026, and FFG-835 on July 23, 2026, only six months apart, demonstrating overlapping construction rather than one-for-one sequential production. Present Korean frigate output is roughly 1-2 ships annually, while simultaneous use of the three principal yards provides a realistic national capacity of roughly 2-3 per year and a potential 3-4 per year surge. U.S. interest has therefore concentrated heavily on industrial capacity. House Appropriations defense personnel visited HD Hyundai on July 10 and Hanwha Ocean on July 11, 2026, while Navy shipbuilding adviser Richard Breckenridge toured Hanwha Ocean, HD Hyundai and SK Oceanplant in late August.

Türkiye’s Istanbul-class is considerably smaller than the Japanese and Korean ships but carries a high weapons density and is already being produced simultaneously at several private yards. The frigate displaces roughly 3,100 tons and measures 113.2 m long, 14.4 m wide and 4.05 m in draft, with roughly 123 personnel. The surface strike battery is unusually large relative to displacement, with 16 Atmaca anti-ship missiles in four quadruple launchers, 16 MiDLAS VLS cells, a 76 mm/62-caliber main gun, a twin 35 mm Gökdeniz CIWS, two 25 mm SMASH remote weapon stations and 324 mm torpedoes. The lead TCG Istanbul uses a shorter tactical-length MiDLAS installation, while TCG Izmir incorporates a deeper strike-length 16-cell installation with sufficient volume for larger Siper-family interceptors and potential vertically launched strike weapons.

If all 16 cells were allocated to a quad-packed smaller interceptor, the theoretical load could reach 64 missiles, although an operational magazine would depend on mission requirements and missile integration. The production history is also compressed. TCG Istanbul was built at Istanbul Naval Shipyard and commissioned on January 19, 2024. Izmir, Izmit, and Içel all began steel cutting on April 10, 2023; Izmir and Izmit were launched on January 10 and January 11, 2025, roughly 21 months after steel cutting, while Içel followed on September 1, 2025. Serial construction then expanded across Anadolu, Sedef and Sefine, and seven İ-class frigates are now simultaneously progressing through three private shipyards. That supports an effective Turkish frigate output of roughly 2-3 ships annually, with 3-4 per year representing a conditional surge. For Washington, the principal issue is not whether Türkiye can fabricate hulls quickly but how much of the Turkish combat system architecture the Navy would retain.

On a 3,100-ton hull with less reserve volume than either the Mogami or the Chungnam, that modification burden could consume much of the schedule advantage created by the original Turkish production rate. China provides the most relevant quantitative benchmark because the PLAN is adding more and more frigates while the U.S. Navy has none in service. The PLAN operates roughly 50 frigates in 2026, predominantly Type 054A ships, compared with zero operational U.S. Navy frigates. The production structure is more important than the inventory total. China commissioned its first Type 054B in January 2025 and the second in March 2025, while at least a third Type 054B is under construction, but Type 054A production did not stop. Another Type 054A entered PLAN service in August 2026. China is therefore overlapping production of the mature Type 054A and the newer Type 054B rather than closing one frigate line before the next reaches volume production.

Both classes are associated with 32-cell VLS installations, giving the PLAN a medium surface combatant fleet with a standardized missile-cell count that the initial U.S. FF(X) is not expected to match through an equivalent fixed 32-cell Mk 41 battery. Long-run Type 054A construction at Hudong-Zhonghua and Huangpu-Wenchong, combined with Type 054B introduction, supports an estimated sustained Chinese frigate rate of roughly 2-4 ships annually. Short periods can produce higher launch or delivery totals when several hulls from both yards reach milestones together. At 2 ships per year, China adds 10 frigates in five years; at 4 per year, it adds 20. If the United States does not begin delivering a new frigate until 2028, the 2026-2028 interval alone corresponds to another 4-8 Chinese frigates at the present estimated rate.

If U.S. hull 3 then requires another three or four years to transition into American production, China could add another 6-16 frigates during that localization interval. The comparison does not mean a Type 054A frigate equals an Arleigh Burke destroyer in combat power. A Burke carries a much larger Mk 41 battery and a higher-end Aegis air defense and strike architecture. The industrial implication is different: China can use dozens of frigates for escort, ASW, patrol, task group screening, and lower-demand far-seas deployments while reserving Type 052D and Type 055 destroyers for missions requiring greater missile capacity and sensor performance. The U.S. Navy frequently assigns Arleigh Burke-class destroyers to missions that do not require the full capability of a DDG, consuming high-end surface-combatant availability.

The central procurement risk is that the U.S. Navy could select a mature foreign frigate and then change enough of it to destroy the maturity it was buying. The Constellation is the immediate precedent. The program began from the Italian FREMM family, displacing approximately 6,000 tonnes at full load, but the U.S. design accumulated enough changes that displacement rose beyond 7,800 tons and construction began before the design was sufficiently complete. The original plan called for 20 ships, but the program was reduced to two hulls in late 2025. The new National Security Cutter-derived FF(X) deliberately moves in the opposite direction, accepting a simpler initial combat configuration to target a first launch in 2028 and attempting to control requirements before construction.

The same discipline would have to govern Mogami, Chungnam, or Istanbul procurement. If the U.S. Navy retains the parent hull, propulsion, major sensors, combat system, and weapons interfaces with only limited U.S. communications and interoperability changes, the foreign shipyard’s existing production data remain relevant. If the Navy instead demands Aegis Baseline 10, EASR or another U.S. radar, Mk 41, ESSM, Standard Missile, Tomahawk, Naval Strike Missile, U.S. EW systems, or other American equipment, the program rapidly becomes a second Constellation-class. Every major substitution introduces structural foundations, electrical load, cooling demand, software integration, electromagnetic-compatibility testing, magazine changes, and additional certification.

On Mogami, the larger hull offers more margin to absorb those changes. On Chungnam, some American components such as the MT30 and Leonardo DRS electric motors already reduce unfamiliarity, but the Korean combat system chain would still require integration decisions. On Istanbul, the smaller hull and high concentration of Turkish sensors and weapons make extensive Americanization proportionally more intrusive. The Navy should therefore place an explicit ceiling on design deviation, like the FF(X), before source selection.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

Explore More Defense News

• Land Defense News
• Naval Defense News
• Defense Aerospace News