The submarines of the Västergötland class were able to fire up to six heavy and six light wire-guided torpedoes at the same time against different targets.

[1] The Västergötland class included the submarines Södermanland and Östergötland.

After significant upgrades, these two submarines were reclassified to a new Södermanland class.

Between 2000 and 2004, Östergötland and Södermanland underwent extensive modifications, were extended by 12 meters and fitted with air-independent Stirling engines.

At the same time, the submarines would be modified to handle international missions with operations in hot and salty waters.