Naval Group Delivers De Grasse, Fourth Suffren-Class Nuclear Attack Submarine, to French Navy

Naval Group delivered the nuclear-powered attack submarine De Grasse to the French defense procurement agency (DGA) and the French Navy on June 24, 2026, at Cherbourg. The boat is the fourth of six Suffren-class submarines ordered under the Barracuda program, which is progressively replacing the Rubis-class attack boats in service since the 1980s.

The handover came four months after De Grasse began sea trials off Cherbourg on February 24, 2026. The submarine was rolled out of its construction hall in May 2025 and completed dockside testing before its nuclear reactor achieved first criticality in December 2025, according to Naval Group. The delivery is recorded in GMN's French Navy event log.

De Grasse measures 99 meters in length and displaces 4,700 tons on the surface and 5,200 tons submerged, with a crew of about 65 sailors plus accommodation for special forces personnel. Its pressurized-water reactor is derived from the plants fitted to France's Triomphant-class ballistic missile submarines and the aircraft carrier Charles de Gaulle. The class is credited with a maximum speed of more than 25 knots, a diving depth in excess of 350 meters, and patrol endurance of around 70 days. Its principal weapons, launched through 533 mm tubes, are:

• MdCN naval cruise missiles for land-attack strikes
• F21 heavyweight torpedoes
• Modernized Exocet SM39 anti-ship missiles

According to Naval Group, De Grasse also introduces an updated SYCOBS combat management system and a new-generation electronic warfare suite compared with earlier boats in the class.

The Barracuda program, managed by the DGA with France's Atomic Energy and Alternative Energies Commission (CEA) responsible for the nuclear propulsion, has now delivered four of its six boats. First-of-class Suffren was delivered in November 2020 and entered active service in June 2022, followed by Duguay-Trouin in April 2024 and Tourville in July 2025. Naval Group states the class is designed for an availability of more than 270 days per year, a significant increase over the Rubis class.

Following delivery, De Grasse will conduct a final verification phase ahead of its formal admission to active service, which French officials expect later in 2026. Like its sister boats, it will be based at Toulon, home of France's attack submarine flotilla and its Mediterranean fleet.

The two remaining submarines of the program, Rubis and Casabianca, are under construction at Cherbourg at different stages of completion, with deliveries scheduled through the end of the decade. Their entry into service will complete the replacement of the Rubis class and give the French Navy a uniform force of six nuclear-powered attack submarines capable of land-attack, anti-ship and anti-submarine missions, as well as special forces operations and intelligence gathering.