HII has been awarded an option year production contract for the US Navy’s Lionfish small unmanned undersea vehicle (SUUV) program, continuing production of the next-generation autonomous underwater system designed for undersea warfare missions.
Lionfish is based on HII’s REMUS 300 unmanned underwater vehicle platform, which was originally developed through a rapid prototyping effort with the US Navy and the Defense Innovation Unit (DIU). The system is designed to support missions including mine countermeasures, intelligence, surveillance and reconnaissance (ISR), anti-submarine warfare and electronic warfare.
The latest contract option extends the Lionfish production program, which reached a milestone in late 2025 with the completion of the 42nd vehicle at HII’s Pocasset, Massachusetts facility. The five-year program has the potential to expand to as many as 200 vehicles, with a total contract value exceeding $347 million.
“The decision to exercise this option year production of the Lionfish program reflects the U.S. Navy’s confidence in the platform’s operational performance, reliability and adaptability,” said Duane Fotheringham , president of the Unmanned Systems group within HII’s Mission Technologies division.
The Lionfish program represents the US Navy’s first transition from an Other Transaction Authority (OTA) prototype effort to full-scale production, according to HII. The company also said Lionfish is currently the only cyber-compliant unmanned underwater vehicle in production for the U.S. Navy.
The REMUS 300 platform uses a modular, open-architecture design that allows rapid integration of new payloads and future technology upgrades. HII said the platform is intended to provide flexibility for evolving mission requirements while maintaining lifecycle cost efficiency.
The REMUS family of unmanned underwater vehicles has been deployed by naval forces worldwide, with HII delivering more than 700 systems to more than 30 countries, including 14 NATO members.
The company said more than 90% of REMUS vehicles delivered over the past 25 years remain in active service.