A 155-pound drone submarine that two people can carry and toss off the edge of a dock dives 1,000 feet and works 30-hour missions hunting sea mines, and the Navy just placed its biggest order of them

Key Points:

• The U.S. Navy awarded a $123.4 million contract to HII on September 24 for additional Lionfish underwater drones, with approximately $1.85 million of the funds set to expire if not obligated before the fiscal year-end on September 30.
• Lionfish, the Navy's designation for HII’s REMUS 300 autonomous submarine, is a lightweight, hand-launchable drone capable of 30 hours underwater endurance at depths up to 1,000 feet, used primarily for mine countermeasures, intelligence gathering, anti-submarine warfare, and electronic warfare.
• The Navy initially contracted nine REMUS 300 vehicles in 2022 with options for up to 200 units over five years; as of late 2025, 42 units have been delivered, and recent orders indicate continued production growth.
• HII expanded its manufacturing facility in Pocasset, Massachusetts, by 25% just two days before the latest contract award, signaling preparation for increased production, with most work done at this site employing about 300 people.
• Lionfish is notable as the Navy’s first program to transition from Other Transaction Authority prototyping to full-scale production and is currently the only cyber-compliant underwater drone in production for the Navy, amidst growing competition in the small underwater drone market.