Japan has strengthened its undersea warfare and maritime surveillance capabilities by introducing a new unmanned underwater vehicle (UUV) into the Maritime Self-Defense Force (JMSDF), underscoring Tokyo’s accelerating push toward unmanned naval systems amid growing regional security challenges.
The JMSDF revealed the acquisition through images shared on social media, showing at least six black, domestically manufactured UUVs lined up at an undisclosed facility. While officials have not released the platform’s formal designation or technical specifications, the vehicles are reported to have a diameter of approximately 533 millimeters—comparable to that of modern heavyweight torpedoes.
The size strongly suggests compatibility with standard submarine torpedo tubes, and the UUV is believed to be capable of being launched and recovered directly from submarines. Such a capability would significantly enhance Japan’s undersea operational flexibility, allowing submarines to deploy unmanned systems for reconnaissance or monitoring missions without exposing themselves to detection.
According to the JMSDF, the UUV is designed for a range of missions including subsea monitoring, maritime security, and intelligence gathering. These roles align closely with Japan’s need to monitor vital sea lanes, protect undersea infrastructure such as communication cables, and track submarine activity in surrounding waters.
“JMSDF is steadily building up defense capabilities, including unmanned assets, to enhance deterrence and response,” the service said in a brief statement accompanying the images. The emphasis on deterrence reflects Japan’s broader defense posture, particularly as undersea competition intensifies in the Indo-Pacific region.
The origins of the new UUV program date back to 2019, when Japan’s Ministry of Defense and its Acquisition, Technology & Logistics Agency (ATLA) initiated parallel development efforts for two types of unmanned underwater vehicles. Ishikawajima-Harima Heavy Industries (IHI) was tasked with developing one design, known as Type-1, while Mitsubishi Heavy Industries (MHI) led development of the second, Type-2 variant.
Initial production units were ordered in 2021, marking a transition from concept development to operational capability. Although it remains unclear which of the two designs has now entered service—or whether both are being fielded—the public disclosure suggests the program has reached a level of maturity suitable for operational deployment.
The addition of these UUVs signals Japan’s intent to integrate unmanned systems more deeply into its naval force structure, complementing crewed submarines and surface vessels while enhancing persistence, reach, and situational awareness beneath the waves.
