HII has been awarded an option-year production contract for the U.S. Navy’s Lionfish small unmanned undersea vehicle (SUUV) program, extending work on the service’s next-generation unmanned underwater platform.
The Lionfish vehicle is based on HII’s commercial REMUS 300 platform, which the company said was originally developed through a rapid prototyping effort with the U.S. Navy and the Defense Innovation Unit.
According to the company, Lionfish is designed for a range of undersea warfare missions including mine countermeasures, intelligence, surveillance and reconnaissance, anti-submarine warfare and electronic warfare.
HII said the Lionfish program reached a production milestone at the end of 2025 with completion of the 42nd vehicle at its Pocasset, Massachusetts facility. The company said the five-year program could scale to as many as 200 vehicles, with a total contract value exceeding US$347 million.
Duane Fotheringham, president of HII’s Unmanned Systems group in its Mission Technologies division, said the option-year decision reflected the Navy’s assessment of the platform’s performance and suitability for changing mission requirements.
HII said Lionfish is the Navy’s first program to transition from an Other Transaction Authority prototype effort to full-scale production, and described it as the first and only cyber-compliant unmanned underwater vehicle currently in production for the service.
The REMUS 300 platform is modular and uses an open-architecture design intended to support payload integration and future upgrades. HII said it has delivered more than 700 REMUS vehicles to over 30 countries, including 14 NATO members, and that more than 90% of systems delivered over the past 25 years remain in active service.
