Between 1997 and 2004, 271 3-car sets, numbered 2000–2270, were delivered to Stockholm by the former Kalmar Verkstad, owned by Adtranz, later acquired by Bombardier Transportation.

The first new rolling stock type for the Stockholm metro since the C14 and C15 stock from the mid-1980s, the C20 was at launch advertised as the Vagn 2000 (English: Wagon 2000) and marketed as the subway car of the future, though the only customer outside of Stockholm would be the Bucharest Metro, with an order for 18 MOVIA 346 trains that would be based upon the C20 in 1999, with an additional 26 units later in 2004.

The C20F and the 270 3-car C20 sets underwent a mid-life refurbishment at the Alstom (formerly Bombardier Transportation) factory in Västerås, Västmanland between 2019 and 2023.

All seat upholstery were replaced and new yellow upholstery to designate priority seating were also introduced, and each refurbished C20 set was retrofitted with 16 CCTV cameras, an increase of 6 such cameras in each car prior to refurbishment.The C20F is a related prototype, built with "FICAS" technology – a highly innovative modular construction that uses a stainless steel skin bonded to a rigid composite core.

This construction results in an extremely thin wall (25mm instead of the C20's 100mm), thereby creating a more spacious interior without altering the outer profile.