The CAT services commenced in 1996 with 16 diesel-hydraulic engine powered, Scania-Danish Automobile Building Silkeborg MidCity Series II 0860S low-floor, wheelchair accessible city buses. In 2001, due to high demand, five Volgren CR226L bodied Mercedes-Benz O 405 NHs were implemented in the CAT fleet along with the Scania-Danish Automobile Building Silkeborg MidCity Series II 0860S. However, the Silkeborg MidCity Series II 0860S and the Mercedes-Benz O405NHs were replaced in August 2005 and July 2006 respectively by 25 Volgren CR228L bodied Mercedes-Benz OC500LEs that are fuelled by compressed natural gas and 16 Volgren CR228L bodied Volvo B7RLEs. In addition to the designated fleet, other Transperth liveried buses can sometimes be used. Between 2013 and 2016, the Perth CAT operated a demonstrator Volvo B5RLEH model as part of a trial. In 2016, a new fleet of 32 Volgren bodied Volvo B8RLEs replaced the Mercedes-Benz OC500LEs.