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French Navy Trains Forces to Hunt Suffren-Class Nuclear Submarine in Realistic Naval Warfare Exercise in Mediterranean.
On May 16, 2025, the waters of the Mediterranean became the scene of a particularly ambitious naval exercise. As part of the Courco/Squale 2025 training, the French Navy’s nuclear-powered attack submarine Suffren was hunted by an inter-allied task force composed of surface vessels and airborne assets specialized in anti-submarine warfare.
The Suffren is the lead submarine of the Barracuda-class, a new generation of nuclear-powered attack submarines developed by Naval Group (Picture source: French Navy)
Organized by the French Navy from April 28 to May 11, this high-intensity training aimed to test the tactical and operational capabilities of participating units within a realistic naval warfare scenario. Far from a mere simulation, the exercise highlighted the growing challenges of undersea warfare in the Mediterranean, a strategic area where nuclear submarines play a central role in deterrence, intelligence gathering, and long-range strike missions.
The Suffren is the lead submarine of the Barracuda-class, a new generation of nuclear-powered attack submarines developed by Naval Group and ordered by France’s Defence Procurement Agency (DGA) to replace the aging Rubis/Améthyste-class submarines that have been in service since the 1980s. Assembled in Cherbourg, the 99.5-meter-long submarine displaces over 5,000 tonnes submerged and was delivered to the French Navy in 2017. It is part of an €8.5 billion program involving the construction of six units to be commissioned every two years until 2027: Suffren, Duguay-Trouin, Tourville, Duquesne, De Grasse, and Dupetit-Thouars. The program aims to provide the French Navy with submarines that are more discreet, versatile, and capable of sustained operations compared to the previous generation.
The Suffren represents a significant technological shift. Powered by a K15 nuclear reactor and a pump-jet propulsion system, it can exceed 25 knots while maintaining a low acoustic signature to evade detection. Its reinforced hull allows it to dive beyond 350 meters, and it can remain at sea for over 90 days. Designed for multiple roles, it can conduct anti-submarine and anti-surface warfare, land-attack missions using MdCN cruise missiles, support special operations with up to 15 commandos and a compatible dry deck shelter, perform intelligence tasks, and escort carrier strike groups or ballistic missile submarines (SSBNs). Its armament includes F21 heavyweight torpedoes, SM39 Exocet missiles, naval mines, and eventually unmanned underwater vehicles (UUVs). The SYCOBS combat system, developed by Naval Group integrates advanced Thales sensors, including the S-CUBE sonar suite, flank array sonars, SEACLEAR obstacle avoidance sonar, VELOX-M8 electronic warfare system, dual optronic masts (SOM/AOM), CANTO-S decoys, and tactical data links such as Link 11 and 16.
In the Courco/Squale 2025 scenario, the Suffren faced a joint task force simulating a submarine-hunting operation under near-realistic conditions. The surface force was composed of the FREMM DA frigates Lorraine and Provence, supported by the support vessel Loire and the chartered vessel Jason. These units were reinforced by two Dutch NH90 helicopters, Caïman helicopters from the French Navy’s 31F and 33F squadrons, a U.S. SH-60 Seahawk, and multiple Atlantique 2 maritime patrol aircraft. The primary objective was to validate the qualification of naval officers in command of complex anti-submarine warfare formations, including both surface and aerial components, within a multinational framework. The Suffren served as the designated adversary, testing detection, coordination, and engagement capabilities of the task force.
This exercise also included a key training element: Courco, short for “cours de commandement,” is the final stage in the qualification process for future commanders of nuclear-powered attack submarines. Officers are evaluated under operational conditions to confirm their ability to lead a submarine in contested environments. This includes maintaining acoustic discretion, executing evasive maneuvers under pressure, and making rapid tactical decisions. The Suffren, with its low observability and modern systems, presented a formidable challenge to the surface and aerial units, making the exercise highly demanding.
The integration of Courco and Squale exercises enables the French Navy to fully exploit the complementarity between submarine forces and inter-allied maritime-air assets. This coordination has become essential, as submarines, particularly nuclear-powered ones, take on an increasingly critical role in naval strategy, from deterrence to high-intensity operations. In a maritime environment such as the Mediterranean, characterized by geopolitical friction, dense commercial traffic, and contested zones, the ability to locate or evade a submarine is a key operational capability for ensuring national and collective security.
Ultimately, Courco/Squale 2025 reflects the French and allied forces' growing capabilities in undersea warfare. The exercise served to assess crew resilience, command chain efficiency, and the tactical relevance of current doctrines in the face of a modern and elusive adversary. The Suffren, as a next-generation platform, has positioned itself as a core asset not only for future training but also for potential operational engagements.