The Strv 103 "zero series" was a preproduction order for the army after the successful display of the S1 and S2 prototypes. 10 units of these series were built, and they were used to test how the Strv 103 would perform in Swedish defense doctrine. The tanks were also tested in order to evaluate logistics, organization, their compatibility with other tank units, and crew training. These trials ended in 1966, following an order placed by the Swedish Army for 70 Strv 103As in 1964. The first batch of these new tanks was delivered in 1967, a year after the "zero series" trials ended.

It was introduced as a pack vehicle in Update 1.95 "Northern Wind". The Strv 103 is a heavily angled tank, with relatively thin armour but a 77-degree slope. This allows the tank bounce most conventional shells like APCBC and even APDS, however it is very vulnerable to HEAT and HEAT-FS projectiles, since those are able to penetrate the tank with ease, and even if the crew is not injured, disabling the engine or transmission immobilizes the tank, and gun, since this is fixed to the hull. So it's better used as a sniper, using its variable suspension to peek over hills and retain a low profile.

The Strv 103-0 was removed from the store after the May 2021 sale but was reintroduced in Update "Direct Hit" as a premium vehicle purchasable in-game for Golden Eagles.