Japan Maritime Self-Defense Force

The Japan Maritime Self-Defense Force (JMSDF) is a technologically advanced fleet that has moved, since the 2022 National Security Strategy, from a strictly defensive posture to one that includes long-range counterstrike. Its missions are the defence of Japan's sea lines of communication, the surveillance of an archipelago stretching more than 3,000 kilometres toward Taiwan, ballistic missile defence, and interoperability with the United States Navy. Record defence budgets and the commitment to reach two percent of GDP have accelerated procurement across every warfare area.

The surface fleet is unusually destroyer-heavy. Eight Aegis ships, the Kongo, Atago and Maya classes, provide fleet air defence and ballistic missile defence, and are now being fitted for Tomahawk land-attack missiles, with integration completed aboard the first destroyer in early 2026. The Izumo and Hyuga classes, officially helicopter destroyers, give Japan a de facto light carrier capability: Izumo's flight deck has been rebuilt in a rectangular configuration for F-35B operations, with work due to finish in 2027 and Kaga following in fiscal 2028. The Mogami-class frigates, highly automated and crewed by about ninety sailors, have entered service in numbers and have been grouped, with other modern combatants, into a new Patrol and Defence Group created in March 2026 to handle grey-zone and standing surveillance tasks.

Submarines remain the core of Japan's deterrent posture. The force is held at around two dozen hulls and is transitioning from the Oyashio and Soryu classes to the lithium-ion battery powered Taigei class, which offers greater submerged endurance and is planned to carry new stand-off missiles. Mine countermeasures, a legacy strength given the confined waters around the archipelago, are being reorganised around uncrewed systems, and the fleet's ocean surveillance and replenishment ships underpin persistent anti-submarine coverage of the approaches to the Pacific.

The main construction effort now runs along three lines. Two Aegis System Equipped Vessels, 12,000-tonne ships laid down in March 2026 for delivery in March 2028 and March 2029, will take over the standing ballistic missile defence watch while carrying Tomahawk and, later, hypersonic interceptors. The upgraded Mogami, or New FFM, extends the frigate programme with a larger hull and thirty-two vertical launch cells, and was selected by Australia in August 2025 for its general-purpose frigate requirement, Japan's first major postwar warship export. Additional Taigei-class boats are funded in successive budgets.

The JMSDF's operational reach is regional but increasingly extended. It sustains anti-piracy deployments and a base at Djibouti, conducts Indo-Pacific Deployment cruises with allied navies, and runs continuous surveillance of Chinese and Russian naval movements through the Miyako, Tsushima and Soya straits. Persistent recruitment shortfalls remain the principal constraint on manning a fleet growing faster than the pool of sailors available to crew it.