U.S. Navy orders $123M more Lionfish underwater drones

The U.S. Navy has ordered another $123.4 million worth of Lionfish small underwater drones from HII, exercising contract options for more vehicles, support equipment and related gear, the U.S. Department of War announced.

Naval Sea Systems Command awarded the firm-fixed-price modification to HII’s Unmanned Systems business on Sept. 24. Nearly all of the work, 99%, will take place at the company’s plant in Pocasset, Massachusetts, with the remaining 1% in Hampton, Virginia, and it is expected to be finished by December 2027. The notice does not say how many vehicles the order covers.

Lionfish is the U.S. Navy’s name for HII’s REMUS 300, a torpedo-shaped autonomous vehicle that two people can carry and launch. HII says the design can dive to 305 meters (1,000 feet) and run missions of up to 30 hours, and that it supports mine countermeasures, intelligence and surveillance, anti-submarine warfare and electronic warfare. Its modular body is built to take different sensor payloads, and it replaces the Mk 18 Mod 1 Swordfish, an older vehicle based on HII’s smaller REMUS 100.

Most of the money, about $114.5 million, comes from fiscal 2025 Navy procurement funds, with another $4 million from Navy research and development accounts. The remaining $4.8 million comes from National Guard and Reserve equipment procurement funds from fiscal 2024 and 2025, and about $1.85 million of that fiscal 2024 money would have expired at the end of this month if it had not been obligated.

The U.S. Navy picked the REMUS 300 for its next small unmanned undersea vehicle in 2022 and awarded HII a Lionfish production contract in September 2023. That deal covered nine vehicles at first, with options that could raise the total to 200 over five years and a maximum value of more than $347 million.

HII delivered the first two vehicles in April 2025 and finished the 42nd before the end of that year, completing the contract’s base-year production. In May, the U.S. Navy exercised an option year worth $36.9 million for more vehicles and support equipment. HII has described Lionfish as the U.S. Navy’s first program to move from an Other Transaction Authority prototype, a faster contracting route used for experimental work, into full-scale production.

The new $123.4 million award is by far the largest single order announced under the program so far. The Pentagon and HII have not said how many Lionfish vehicles it buys, how many the U.S. Navy now plans to field in total, or which units will receive them.