The Swedish Södermanland class of diesel-electric submarines consists of and . They are one of two subclasses/derivations of the s of the Swedish Navy originally designed and built in the 1980s.

Design These two submarines were originally launched as s in 1987 and 1990, and were relaunched as a new class after extensive modernization in 2003 and 2004 by Kockums AB. The pressure hull had been cut in two after the sail and a long new section with an air-independent propulsion system was inserted. It contains two Stirling engines which are coupled to electric generators and heated by burning diesel fuel with liquid oxygen stored in cryogenic tanks. The AIP system can provide electric energy to extend the submarine's submerged time from days to weeks. Two submarines of similar design, known as the are in service with the Republic of Singapore Navy.

Operational History , Södermanland is planned to remain in service until at least 2024-25 when it was to be replaced by the future s. However, the Östergötland was decommissioned in 2021, and is in material reserve.

Lease to Poland In late November 2025, Sweden and Poland reached an agreement linked to Poland's planned acquisition of three A26 submarines under the Orka programme by the Polish Navy to replace its older Kilo class Submarine ORP Orzel, in which Sweden would provide the ageing but still operational submarine HMS Södermanland as an interim “gap-filler”. According to the report, Poland is expected to gain access to the vessel around 2027, temporarily reducing Sweden's submarine fleet by one unit for several years; Swedish Defence Minister Pål Jonson stated that this temporary gap would not weaken Sweden's strategic position in the Baltic Sea.

Units Ship nameLaid downLaunchedCommissionedServiceStatus 12 April 198821 April 19891st Submarine FlotillaRefitted 2003, Active and to be leased to Poland, underwent life-extension and re-launched in 2024 allowing for service until 2030 9 December 198819891st Submarine FlotillaRefitted 2004, Decommissioned 2021

References

Further reading

External links Kockums page about the Södermanland class Kockums AIP Stirling system