Hitachi, headquartered in Tokyo, has contracted Huntington Ingalls Industries (HII) to supply more than a dozen REMUS 300 small uncrewed undersea vehicles (SUUVs) under a multi-year deal, underscoring the enduring defense partnership between Japan and the US. It has not been confirmed whether these units are intended for the Japan Maritime Self-Defense Force. The REMUS 300, chosen by the US Navy for the Lionfish program, offers modular flexibility for quick payload changes and future adaptability. Designed for endurance, the vehicle can reach depths of 305 meters, operate for up to 30 hours, and is powered by a 4.5-kilowatt-hour Lithium-ion battery. It achieves speeds of up to 5 knots with a range of 165 kilometers. Alternate battery configurations reduce its capabilities. At just over 2 meters in length, the SUUV can operate alongside crewed submarines, enhancing mission reach while lowering detection risk.
