France Begins Sea Trials of Fourth Barracuda Nuclear Attack Submarine

The French Defence Procurement Agency (DGA) launched the first sea trial of the nuclear attack submarine De Grasse on February 24, marking the start of full sea trials under the Barracuda program.

The trial follows the completion of construction work and a series of dockside tests conducted in Cherbourg. The submarine was transferred from Naval Group’s construction hall to the launching dock in May 2025 and later launched in the Cachin basin after tests verified the functioning of its systems, watertightness, and propulsion. On December 12, 2025, the vessel’s nuclear reactor underwent its first criticality test, marking its initial start-up.

The De Grasse is the fourth of six Suffren-class submarines being built under the Barracuda program. The final two boats, Rubis and Casabianca, are currently under construction, with deliveries expected by 2030 in line with France’s 2024–2030 Military Programming Law.

Initial sea trials will take place in the English Channel before moving to the Atlantic Ocean. The trials are being supervised by engineers and technicians from the DGA and the Atomic Energy and Alternative Energies Commission (CEA), including its Military Applications Division, in coordination with Naval Group and TechnicAtome. French Navy submariners are conducting the operations at sea. The trials are intended to progressively verify the submarine’s technical and operational capabilities and will continue until its planned delivery to the French Navy in 2026.

As prime contractors for the Barracuda program, the DGA and the CEA are responsible for the testing phase through to final acceptance and delivery. During this period, the submarine remains the property of Naval Group and TechnicAtome. The French Navy, acting as the delegated operator of the military nuclear system, holds command and operational control.

The Barracuda-class submarines are nuclear-powered attack submarines designed to replace the Rubis-class SSNs that entered service from the 1980s. The first three boats in the program — Suffren, Duguay-Trouin, and Tourville — entered active service in June 2022, April 2024, and July 2025, respectively.

The six submarines ordered under the Barracuda program are intended to renew France’s nuclear attack submarine fleet by 2030.