Navantia lays keel for Poseidón-class submarine rescue ship

A block of the future submarine rescue ship Poseidón during the keel-laying ceremony for the ship on 27 November in Puerto Real. (Navantia)

Navantia held a keel-laying ceremony for Poseidón (A 21), the Spanish Navy's future submarine rescue ship, on Thursday 27 November 2025. The ceremony was held at at its Puerto Real facility, the shipyard announced on the same day.

Poseidón , also referred to as BAM-IS (Buque de Acción Marítima Intervención Subacuática), is intended to replace the navy's ageing support ship Neptuno and to provide support for the Isaac Peral (S-80 Plus)-class submarines. The keel-laying marks the latest milestone for the project following the steel cut for full rate production in December 2024.

The new ship will have a displacement of 5,000 tonnes, a length of 92 m, and a top speed of 15 kt. Propulsion is to be a direct current based electric system using ABB energy storage systems and Voith Schneider cycloidal thrusters. The design also includes a helipad and 400 m ² working deck, with the latter capable of being reconfigured for modular payloads and tasks including submarine rescue and salvage, dive support, underwater heritage protection, transport, and sea pollution assistance.

In a first for the Spanish Navy, Poseidón is to also be capable of acting as a mother ship for the NATO Submarine Rescue System (NSRS) and NATO Submarine Rescue Diving and Recompression System (SRDRS). Equipment is to also include side-scan sonar, two hyperbaric chambers, an autonomous underwater vehicle (AUV), two remotely operated vehicles (ROVs), two underwater communication systems, emergency supply systems, and three rigid hull inflatable boats (RHIBs).

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