On Thursday, November 27, 2025, the Spanish Ministry of Defense announced on social media the start of port and sea trials for the newest submarine, Narciso Monturiol (S-82), of the S-80 Plus class – the second of four ordered in total.
Photos: Spanish Ministry of Defense
The Spanish Ministry of Defense originally ordered four submarines under the S-80 program on March 24, 2004. The keel of the prototype vessel was laid in 2005, and delivery was initially planned for 2011 (later revised to 2015 for financial reasons). However, in 2013 a serious design flaw was discovered, requiring a redesign (hence the S-80 Plus designation), which significantly extended the construction timeline – at least until 2017 (a deadline that also proved unattainable).
Finally, on April 22, 2021, two days after the submarine was rolled out of the Navantia assembly hall in Cartagena, the christening ceremony took place, followed by its launch on May 7 of the same year. Propulsion trials on the tether began in February 2022, diving trials in March 2023, and on November 30 of that year, the submarine entered service as Isaac Peral (S-81) at the FLOSUB (Flotilla de Submarinos) submarine flotilla base in Cartagena.
Over the course of the program, the costs of building the four submarines also increased. The original 2004 contract estimated a total cost of 1.756 billion EUR, or 439 million EUR per vessel. By 2010, the figure had risen to 2.212 billion EUR (553 million per submarine); in 2014, to 3 billion EUR (750 million per submarine); and by 2018, to 3.935 billion EUR (983.75 million per submarine).
As a result, construction of the Narciso Monturiol (S-82), which began on February 19, 2009, was only completed with its christening and launch on October 3 of this year. Delivery is scheduled for 2026. Meanwhile, the remaining two, Cosme García (S-83) and Mateo García de los Reyes (S-84), have been under construction since 2010 and 2011, with planned deliveries in 2028 and 2029.
With a hull length of 80.80 meters and a displacement of about 2,400 tons, the S-80 Plus submarines are among the largest Western conventionally powered submarines. The original design envisioned a length of 71 meters and a displacement of 1,740 tons. The changes resulted from the discovery that the submarines would be 75–100 tons heavier than planned, which threatened their buoyancy. With assistance from specialists at General Dynamics Electric Boat in Groton, three new hull sections were added. The redesign was declared complete in September 2014, and in 2016 the Ministry of Defense resumed the construction program.
The S-80 Plus is equipped with an air-independent propulsion (AIP) system known as BEST (Bio-Ethanol Stealth Technology), generating 300 kW. It is based on UTC Power fuel cells that use hydrogen produced from bioethanol reforming, along with a bioethanol reactor from Abengoa Innovation. The submarine also has three diesel engines, each rated at 1,200 kW. Interestingly, the BEST AIP system will be installed immediately on the third vessel in the series, while the first two will receive it only during their major overhauls. Until then, they will use the onboard 3,500 kW electric motor.
The armament of the new submarines consists of 533 mm heavy torpedoes DM2A4 Seehecht and Mark 48, UGM-84 Harpoon anti-ship missiles, and SAES naval mines. It had previously been planned that they would also be armed with UGM-109 Tomahawk cruise missiles for land-attack missions.
The S-80 Plus submarines will replace the last remaining S-70 Galerna–class submarine (the French Agosta 90B type) still in service—Galerna (S-71), which underwent repair and modernization between 2017 and 2022. The three earlier units of this class were withdrawn earlier: Siroco (S-72) in 2012, Mistral (S-73) in 2020, and Tramontana (S-74) in 2024 (Spain nearly without submarines).
The S-80 Plus was also unsuccessfully offered to Poland under the Orka program.
El submarino S-82 ‘Narciso Monturiol’ avanza con éxito en sus pruebas de puerto y mar.
Tras su maniobra de puesta a flote en Cartagena, ahora @NavantiaOficial verifica todos sus sistemas para preparar la entrega a la @Armada_esp. pic.twitter.com/FGnBwRpeyg
— Ministerio Defensa (@Defensagob) November 27, 2025
Buen trabajo, bienvenidos a casa. https://t.co/3Am4o0u4Go
— Ministerio Defensa (@Defensagob) November 28, 2025
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