Originally launched as the Swedish Navy Västergötland-class submarines HSwMS Hälsingland and HSwMS Västergötland in 1986 and 1987, the two submarines were sold to Singapore in November 2005 and relaunched in June 2009 and October 2010 respectively after extensive modernisation by Kockums, which included a refit to Södermanland class standards, the insertion of a new hull section with an air independent propulsion system, and additional climatisation for use in tropical waters.

Singapore's Ministry of Defence (MINDEF) signed an agreement with Kockums for the supply of two Archer-class (formerly Västergötland-class) submarines to the RSN on 4 November 2005.

[1] More than 20 years old and previously in reserve with the Swedish Navy, the submarines were transferred to the RSN on completion of the modernisation and conversion for operation in tropical waters.

[2] RSS Archer underwent sea trials following its launch and is now operational.

The advanced sonar system allows the submarines to detect contacts at a further distance, while the torpedo system has a better target acquisition capability, which allows the submarines to engage contacts at a longer range.