Poland to lease HMS Sodermanland submarine from Sweden until first Saab A26 arrives.

Poland will lease the submarine HMS Södermanland from Sweden as a bridge to its future Saab A26 fleet, a move confirmed by the Swedish Navy on June 2, 2026, that helps prevent a dangerous erosion of undersea warfare expertise while new submarines are still under construction. The arrangement gives the Polish Navy an operational vessel for training and force generation years before the first A26 enters service, preserving a critical combat capability in the Baltic region.

The rebuilt submarine brings air-independent propulsion technology, modern submarine operating practices, and relevant combat-system experience that closely align with the capabilities Poland will field on the A26 Blekinge-class submarine. By training crews, engineers, and maintainers on an operational AIP-equipped submarine, Warsaw can accelerate readiness, strengthen long-term sustainment capacity, and enter the next generation of submarine warfare with a trained force already in place.

Related topic: Saab to supply three A26 Blekinge-class submarines to Poland to improve Baltic Sea security

Polish submarine personnel will begin formal training in Karlskrona in August 2026, HMS Södermanland is expected to transfer in 2027, and the submarine will remain available until the first Polish A26 enters service. (Picture source: Swedish MoD)

On June 2, 2026, the Swedish Navy confirmed that Poland will lease the submarine HMS Södermanland from the Swedish Armed Forces as part of the wider submarine package associated with Warsaw's November 2025 selection of three Saab A26 submarines under the Orka program. The lease addresses a specific problem facing the Polish Navy: the gap between the declining operational value of its existing submarine force and the lengthy construction timeline required to field an entirely new class of submarines. Under the arrangement, Polish submarine personnel will begin formal training in Karlskrona in August 2026, HMS Södermanland is expected to transfer in 2027, and the submarine will remain available until the first Polish A26 enters service.

The project combines the temporary transfer of a submarine with crew training, technical education, maintenance preparation, industrial participation, and long-term cooperation between the Swedish and Polish submarine communities. Rather than waiting until the first A26 is delivered, Poland will gain several years to build crews, instructors, engineers, maintenance organizations, and operational procedures before the new submarines arrive, resulting effectively in a force-generation program built around an operational submarine. The urgency behind the agreement becomes clear when examining the current state of Poland's submarine force.

Today, ORP Orzeł remains the only operational submarine in Polish service. The submarine is a Soviet-built Project 877E Kilo-class boat commissioned during the 1980s and represents the last remaining element of what was once a larger Polish undersea force. The retirement of the Kobben-class submarines removed four additional boats from service and, equally important, reduced the number of available training billets, instructor positions, and maintenance opportunities that sustain long-term submarine competence. Submarine forces differ from many other naval capabilities because crews cannot be generated rapidly once experience is lost.

Commanding officers, engineering officers, sonar operators, weapons specialists, and maintenance technicians typically require years of operational experience before reaching full proficiency. Poland's November 2025 selection of the A26 solved the question of future fleet replacement, but it did not solve the problem of preserving submarine expertise during the years separating contract signature from fleet introduction. The Södermanland lease is therefore intended to prevent a situation in which Poland receives modern submarines but lacks sufficient experienced personnel to operate them at full capability from the outset. The submarine selected for the transition role is significantly different from the vessel that originally entered Swedish service.

HMS Södermanland was commissioned on April 21, 1989, as the third submarine of the Västergötland-class. Between 2000 and 2004, however, the submarine underwent a reconstruction effort substantial enough to create an entirely new class. The pressure hull was cut and lengthened by approximately 12 meters, increasing overall length from roughly 48.5 meters to 60.5 meters. Submerged displacement increased to approximately 1,500 tonnes. The reconstruction introduced an air-independent propulsion (AIP) system and required modifications extensive enough for the submarine to be redesignated as a Södermanland-class vessel rather than remain part of the Västergötland-class.

This distinction matters because Poland is not receiving a submarine preserved in its original late-Cold War configuration. Instead, Polish crews will train on a submarine rebuilt around technologies and operating concepts that remain directly relevant to modern Western conventional submarine operations. In practical terms, the gap between HMS Södermanland and the future A26 is considerably smaller than the gap between ORP Orzeł and the A26. The most important operational change concerns propulsion and underwater endurance. ORP Orzeł relies on a conventional diesel-electric propulsion system that requires periodic snorkeling to recharge batteries.

HMS Södermanland incorporates two Kockums Stirling air-independent propulsion units, which fundamentally change how a submarine is operated. A conventional diesel-electric submarine must periodically expose a snorkel mast above the surface to run diesel generators and recharge batteries. An AIP-equipped submarine can remain submerged for substantially longer periods while generating electrical power without snorkeling. This changes patrol planning, intelligence collection, surveillance operations, and tactical employment, as underwater endurance measured in weeks rather than days becomes a realistic planning factor. Crew routines, engineering procedures, maintenance requirements, and energy management practices are all affected.

The significance of the lease, therefore, lies not only in transferring a submarine but also in exposing Polish crews to the operational realities of AIP-based submarine operations years before the first A26 is delivered. Since the future Polish A26 fleet will also employ Stirling AIP technology, the training received aboard Södermanland directly supports future operational requirements. HMS Södermanland also provides a relevant environment for Swedish weapons, sensor, and combat system training. The submarine carries six 533 mm torpedo tubes and three 400 mm torpedo tubes, giving it a larger torpedo armament than the future A26 design, which is planned to carry four 533 mm tubes and two 400 mm tubes. Crew complement, for its part, normally ranges between 24 and 28 personnel.

The submarine is capable of anti-surface warfare, anti-submarine warfare, surveillance, reconnaissance, and mine-laying missions. Training programs planned for Polish personnel extend beyond navigation and seamanship and include combat system operation, weapons procedures, engineering support, submarine safety, and submarine rescue. One notable feature of the program is the decision to begin with technical personnel before operational crews. This reflects the reality that maintenance expertise often requires more time to develop than crew proficiency. Modern submarines depend on extensive support organizations capable of conducting maintenance, managing spare parts, supporting dockyard activities, and troubleshooting complex onboard systems.

A navy can train a submarine crew relatively quickly compared with the years required to build an experienced maintenance structure. The sequencing adopted by Sweden and Poland indicates that sustaining the future A26 fleet is being treated as a priority equal to operating it. However, the transfer carries measurable consequences for Sweden's own submarine force. Following the retirement of the second Södermanland-class in 2021, the HMS Östergötland, Sweden's operational submarine inventory consists of three Gotland-class submarines and one active Södermanland-class submarine. Leasing HMS Södermanland therefore reduces Sweden's active force from four submarines to three until replacement capacity becomes available.

This reduction becomes more significant when viewed alongside Sweden's recent investments in the vessel. In September 2022, Swedish authorities approved a second life-extension effort for HMS Södermanland valued at approximately SEK 470 million, which included overhaul activities, battery replacement, battery development, and additional work intended to preserve operational availability for several more years. The scale of the investment indicates that Swedish planners expected the submarine to remain active well into the late 2020s. The decision to transfer the vessel despite those investments suggests that supporting the Polish transition to the A26 has been judged more valuable than retaining a fourth operational submarine during the interim period.

Until the arrival of HMS Blekinge and HMS Skåne, Sweden will therefore rely entirely on its three Gotland-class submarines to sustain operational submarine availability. The lease is inseparable from the broader A26 program, also known as the Blekinge-class, and from Poland's emergence as the first export customer for the class. Poland announced the selection of three A26 submarines in November 2025, while Sweden is simultaneously building two submarines of the same family, HMS Blekinge and HMS Skåne. Current schedules place Swedish deliveries in 2031 and 2033. The Polish submarines will be constructed by Saab Kockums in Karlskrona with participation from Polish industry, creating a common industrial and operational ecosystem around the A26 design.

Shared logistics, common maintenance procedures, compatible training systems, and coordinated future upgrades become more practical when two Baltic Sea navies operate the same submarine class. HMS Södermanland functions as the bridge between these two phases: the political decision to acquire the A26 and the eventual introduction of the new fleet. Historically, Sweden has employed similar approaches during submarine exports. Australia received extensive training support in connection with the Collins-class submarines, which were derived from the Västergötland-class.

Denmark leased the submarine Näcken, redesignated as Kronborg, between 2001 and 2005 while developing its own submarine competence. Singapore received years of training support before taking delivery of former Swedish submarines Västergötland and Hälsingland following modernization work. The Polish arrangement follows the same model. The objective is not simply to deliver three submarines, but to ensure that when those A26 submarines arrive, Poland already possesses trained crews, qualified instructors, experienced maintainers, established operational procedures, and a functioning support structure capable of sustaining a modern submarine force from the first day of service.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.