As 2025 came to an end, HII engineers and technicians in Pocasset, Massachusetts, celebrated the completion of production of the 42nd Lionfish small unmanned underwater vehicle (SUUV) for the U.S. Navy. This milestone represents the final base-year Lionfish to be delivered under a five-year program that could scale to 200 vehicles, with a total contract value exceeding $347 million.

Lionfish is based on HII’s REMUS 300 platform, a modular, open-architecture SUUV engineered for multi-mission adaptability. The platform was developed in collaboration with the U.S. Navy and the Defense Innovation Unit (DIU) to accelerate the adoption of dual-use commercial technologies into U.S. Department of Defense programs.

HII delivered the first two Lionfish vehicles in April of this year. 

The Lionfish program has been recognized as the U.S. Navy’s first successful transition from an Other Transaction Authority (OTA) prototype to full-scale production. Lionfish is also the first, and only, cyber-compliant unmanned underwater vehicle.