Japan Begins Development of Submarine-Launched Ballistic Missile Systems

Development has begun in Japan on a Vertical Launch System (VLS) for a future class of conventionally powered diesel-electric submarines.

According to Japan’s Ministry of Defense, the new VLS is being designed with the potential capability to launch Hyper Velocity Gliding Projectile (HVGP) ballistic missiles. The land-based version of this missile is designated Type 25.

The project will be carried out from 2026 to 2029, with total research costs estimated at 3.9 billion yen (approximately $24.8 million).

The main challenge for engineers is to ensure the submarine remains difficult for enemy radar to detect while maintaining its maneuverability and stability during missile launches.

To reduce costs and accelerate development, engineers will validate the design using a high-fidelity virtual simulation environment that accurately replicates operational conditions.

The engineers are developing the vertical launch system to accommodate multiple missile types, including the naval variant of the Hyper Velocity Gliding Projectile (HVGP), as well as cruise missiles and hypersonic missiles.

According to the officially released rendering, the system will feature 7 to 8 vertical launch cells per module. The submarine is expected to carry 2 to 3 VLS modules, providing a total of 14 to 24 missile cells.

In 2023, Kawasaki Heavy Industries unveiled a concept for a next-generation submarine, described as Japan’s first design with enhanced land-attack capabilities. The concept also featured a larger hull, an improved propulsion system, and enhanced overall performance.

Currently, the only missile armament carried by Japanese submarines consists of U.S.-made Harpoon anti-ship missiles, which are launched from 533 mm torpedo tubes.

On October 15, 2025, Kawasaki Heavy Industries launched JS Sogei, the sixth Taigei-class submarine equipped with lithium-ion batteries. Its primary armament consists of six 533 mm torpedo tubes.

The submarine is also expected to receive the new Type 12 SSM-ER long-range cruise missile, production of which Kawasaki Heavy Industries recently began for both surface combatants and submarines.