Japan is considering the development of a new hypersonic guided missile (HGM) designed for launch from underwater platforms, according to a budget request submitted by the nation’s Ministry of Defense. The initiative could strengthen Japan’s ability to conduct sea-based stand-off operations while adding another potential long-range strike option to its defense architecture. No technical information about the proposed missile has been disclosed so far. However, the weapon is expected to build on the technologies and development experience associated with Japan’s Type 25 Hyper Velocity Gliding Projectile, or 25HGP. The domestically developed 25HGP is being pursued primarily for remote island defense and extended stand-off deterrence. The planned underwater-launched HGM would represent a further evolution of Japan’s interest in long-range precision weapons, potentially allowing such systems to be deployed from platforms operating below the ocean surface. While details such as range, propulsion, launch method, and dimensions remain undisclosed, the inclusion of the project in the defense budget request signals Tokyo’s intention to explore additional submarine-based strike capabilities.
