HII Wins $123 Million Navy Modification for Lionfish Small Undersea Vehicles

HII Unmanned Systems has received a $123,365,000 Navy contract modification to build more Lionfish small unmanned undersea vehicles, along with support and ancillary equipment. The award appeared in the Pentagon’s contract announcement for 29 September and was made on 24 September.

The firm-fixed-price modification to contract N00024-23-C-6308 exercises options on the Lionfish program. Naval Sea Systems Command in Washington is the contracting activity, and the work is expected to finish by December 2027.

How Much Is the HII Lionfish Contract Modification Worth?

The notice lists four funding lines totalling the full $123,365,000. Most of it, about $114.5 million, is fiscal 2025 Navy other procurement money. Smaller amounts come from research and development and from National Guard and Reserve equipment accounts. Of the total, $1,852,675 expires at the end of the current fiscal year.

What Is the Lionfish Small Unmanned Undersea Vehicle?

Lionfish is the US Navy’s name for its next-generation small unmanned undersea vehicle, or SUUV. It is built on HII’s commercial REMUS 300, a two-person portable, open-architecture design. According to Naval Technology, the REMUS 300 was chosen as the Navy’s SUUV program of record in March 2022 after a two-year rapid prototyping effort run through the Defense Innovation Unit. It replaced the Mk 18 Mod 1 Swordfish, which was based on the older REMUS 100.

HII lists mine countermeasures, intelligence, surveillance and reconnaissance, anti-submarine warfare and electronic warfare as Lionfish missions. Public references put the REMUS 300 at about 2.3 metres long and 19 centimetres in diameter, with a 305-metre depth rating and endurance of up to 30 hours. Those figures describe the commercial REMUS 300, and the Navy has not published Lionfish-specific numbers in the sources reviewed.

Lionfish Program Timeline From Prototype to Production

HII says Lionfish was the Navy’s first transition from an other transaction authority prototype effort to full-scale production, and that it is the first and only cyber-compliant unmanned underwater vehicle in production for the Navy. Those are company statements.

The July 2026 announcement did not state a dollar value, and the September notice does not say whether this $123.4 million modification is that same option year or a further one. That link is unconfirmed.

Who Is HII Unmanned Systems and What Is Its Hydroid Heritage?

The Pocasset operation began as Hydroid, maker of the REMUS line of vehicles, which have been in operation since 2001. HII announced on 4 February 2020 that it would buy Hydroid from Kongsberg Maritime for $350 million, a price it said fell by about $50 million after tax benefits. After the purchase it became part of HII, and the Pentagon notice now lists the unit as Huntington Ingalls Industries Unmanned Systems. HII says it has delivered more than 700 REMUS vehicles to over 30 countries, 14 of them NATO members.

How Does This Fit the Navy’s Push for Uncrewed Systems?

Analysis: a nine-figure exercise of options shows the Navy is treating small undersea vehicles as a production item rather than an experiment. HII said in July that the option decision reflected “the U.S. Navy’s confidence in the platform’s operational performance, reliability and adaptability,” a company claim. The same company is also part of the surface side of the effort, having been among the builders in the Navy’s order for 30 medium unmanned surface vessels.

Lionfish SUUV FAQ

How much is the HII Lionfish contract modification?

$123,365,000, a firm-fixed-price modification to contract N00024-23-C-6308 awarded on 24 September 2026.

What is the Lionfish SUUV based on?

HII’s REMUS 300 vehicle, selected as the Navy’s small unmanned undersea vehicle program of record in 2022.

Where will the work be done?

99 percent in Pocasset, Massachusetts, and 1 percent in Hampton, Virginia, with completion expected by December 2027.

How many Lionfish vehicles will the Navy buy?

The program could reach 200 vehicles over five years, according to HII. The September notice does not state how many vehicles this modification covers.

What was Hydroid?

The company behind the REMUS vehicle line, bought by HII from Kongsberg Maritime in 2020 for $350 million and now HII Unmanned Systems.