The S-81 is the lead ship of the S-80 class, a series of four submarines commissioned by Spain’s Ministry of Defence and built by the state-owned shipbuilder Navantia. The submarine was formally handed over to the Spanish Navy during a ceremony at Arsenal Militar de Cartagena on 30 November 2023.
Operation Sea Guardian is overseen by NATO’s Allied Maritime Command in Northwood, United Kingdom. The mission focuses on maritime security capacity-building, enhancing situational awareness at sea, and counter-terrorism operations.
“This is the submarine’s first long-term operation as part of NATO maritime cooperation forces,” the Spanish Navy said. The deployment reflects Spain’s growing role in multinational maritime defence initiatives.
The S-81 measures 80.81 metres in length and displaces 2,965 tonnes submerged. It is equipped with six NATO-standard 533 mm torpedo tubes capable of launching heavy torpedoes, anti-ship missiles, and cruise missiles against distant land targets, and can also deploy naval mines.
The submarine features acoustic decoy launchers designed to confuse homing torpedoes, enhancing its survivability. The vessel is also prepared for future integration of land-attack cruise missiles, expanding its operational versatility.
Construction is progressing on the rest of the S-80 series, including the S-82 Narciso Monturiol, recently christened and being readied for launch in Cartagena. Two more submarines are under construction, including the S-83 Cosme García, which will be the first equipped with the AIP BEST (Bio-Ethanol Stealth Technology) air-independent propulsion system.
This AIP system will allow submerged operations for up to three weeks without surfacing, using onboard fuel cell technology powered by stored oxygen and hydrogen derived from bioethanol reforming. It will be the world’s first operational AIP system with fuel cells and onboard hydrogen generation in sufficient quantities for sustained operation.
Talks are ongoing between Navantia and Spain’s Ministry of Defence regarding the potential purchase of two additional S-80 submarines. This would further expand Spain’s underwater warfare capabilities in NATO and beyond.
