S-80 Plus-class (Isaac Peral-class)

The S-80 Plus class (also designated the Isaac Peral class) is a series of four air-independent propulsion (AIP) submarines built by Navantia at the Cartagena shipyard for the Spanish Navy. The S-80 Plus class originated from a joint venture in the late 1980s between Bazán (later Navantia) and French shipyard DCNI, which produced the Scorpène-class design exported to Chile. In 1998, Spain revised its naval requirements to prioritize power projection over static defense, leading to the larger S-80A design. The Spanish government ordered four S-80A submarines in September 2003, signing a construction contract with Izar on March 24, 2004. In May 2013, Navantia identified a 100-tonne weight miscalculation. To resolve this issue, Navantia contracted the American company General Dynamics Electric Boat, resulting in a redesign that lengthened the hull by 10 meters and established the S-80 Plus standard.

These submarines utilize the VC 9.0 SCA Integrated Combat System Core (ICSC) to coordinate active and passive sonars, electromagnetic detection systems, and Link-11 and Link-22 data links. The propulsion system features an AIP system designed by Abengoa subsidiary Hynergreen, which processes bioethanol and liquid oxygen to produce hydrogen for UTC Power fuel cells. No boat has yet been fitted with the system: Isaac Peral was delivered without it and installation is planned as a later retrofit. Carbon dioxide byproducts are dissolved in seawater using Bionet's SECO2 removal system. S-80 Plus-class boats are propelled by a permanent-magnet electric motor mounted on flexible Vulkan RATO-S G-561W couplings to minimize acoustic signature. Armament options for the six 533 mm torpedo tubes include DM2A4, Mark 48, Black Shark, Spearfish, or Torped 2000 torpedoes, alongside UGM-84 Sub-Harpoon Block II or Exocet anti-ship missiles, Tomahawk cruise missiles, and MINEA smart bottom mines.

The first submarine of the S-80 Plus class, Isaac Peral (S-81), began construction on December 13, 2007, launched on April 22, 2021, and entered service with the Spanish Navy on November 30, 2023. The second boat, Narciso Monturiol (S-82), was floated out on 3 October 2025 and completed her first static dive at Cartagena on 31 July 2026, with delivery still targeted for 2026. The remaining units, Cosme García (S-83) and Mateo García de los Reyes (S-84), are scheduled to enter service in 2028 and 2029, respectively. Internationally, the S-80 Plus class has been offered to the Philippine Navy with a proposed base in Ormoc, Leyte. Bids for the Indian Navy's Project-75 and the Netherlands' Walrus-class replacement program were unsuccessful. In November 2025, Poland also rejected the design for its Orka program, selecting the A26 Blekinge instead.