Japan targets hypersonic strike capability for its submarine fleet

Japan’s Ministry of Defence has requested funding in the fiscal 2027 budget to develop a hypersonic missile designed for deployment on submarines, in a move aimed at strengthening the long-range strike capabilities of the country’s submarine fleet.

Although the official budget request document has yet to be released, the proposed program would mark a new phase in Japan’s efforts to equip its submarines with advanced long-range weapons, Militarnyi reports.

The initiative comes as the Defence Ministry seeks a record ¥8.9 trillion ($60.1 billion) budget for fiscal 2027 to strengthen the Self-Defence Forces and accelerate the development of capabilities for emerging forms of warfare.

Japan is already developing a vertical launch system for submarines capable of firing multiple types of missiles, including cruise, ballistic and hypersonic weapons. According to an official rendering released by the Defence Ministry, each launch module is expected to contain seven to eight missile cells. A submarine could be equipped with two to three such modules, providing a total capacity of 14 to 24 missiles.

Development of Japan’s hypersonic weapons has been underway since 2019. In December 2025, the Defence Ministry announced that it had begun mass production of new hypersonic guided missiles as part of efforts to enhance the country’s long-range defence capabilities.

While the full development cycle for the weapons is not expected to be completed until fiscal 2031, Japan has opted to accelerate deployment following successful interim research results from a program launched in 2023.

The submarine vertical launch system is also under development. According to Militarnyi, research is scheduled to continue from 2026 through 2029, with total development costs estimated at approximately ¥3.9 billion ($24.8 million).

The system is being designed to accommodate different classes of missiles, including naval variants of the Hyper Velocity Gliding Projectile (HVGP), as well as cruise and hypersonic missiles.

Japan has simultaneously expanded its acquisition of long-range cruise missiles. In October 2025, the Defence Ministry awarded a contract for mass production of 12SSM-ER missiles intended for deployment aboard surface warships and submarines.

The 12SSM-ER is expected to become a standardized long-range strike weapon for Japan’s Maritime, Air and Ground Self-Defence Forces, reflecting Tokyo’s broader effort to strengthen stand-off strike capab

By Vafa Guliyeva