Toyota began development of assisted-mobility vehicles in the 1960s by commissioning specialty manufacturers to add modifications such as drive-assist devices and lifts. The customers for such vehicles were mainly nursing care facilities and other institutions and demand was met by creating assisted mobility versions of the Townace van and other vehicle series, which were fitted with wheelchair lifts and other features.

Subsequently, as demand from individual customers increased with the advance of demographic aging, more vehicle models were introduced to support nursing care with passenger seats that rotate and slide down and to the outside of the vehicle, and other features. By 1996, the introduction of such features in all van and minivan vehicle series was complete. Toyota then proceeded with rollout to all vehicle series including compact cars and other vehicles.

In 1997, the enactment in Japan of the Long-Term Care Insurance Law brought increased demand for assisted-mobility vehicles. In the same year, Toyota made a television commercial showing a family taking its wheelchair-using grandfather on an outdoor excursion, thus promoting the corporate message "creating people-friendly vehicles".

In 1998, Toyota's series of assisted-mobility vehicles were given the name "Toyota Welcab Series Vehicles" as a way of promoting increased recognition. As a result, people started requesting to be able to get a better look at the Welcabs (as the vehicles were known in short). To meet this demand, in July of the same year, Toyota Heartful Plaza opened in Tokyo's Suginami-ku, an exhibition center with a display space for approximately 10 vehicles from the Welcab series. Similar facilities were later rolled out nationwide, promoting increased sales of Welcab series vehicles.

Annual sales of Toyota assisted-mobility vehicles were around 2,700 units in 1996, but grew to 13,790 units in 2000.

Toyota rental and lease dealers introduced 80 Welcab rental vehicles in 1996, but, by the end of 2006, the number had increased to 800, the highest in the car rental industry, a fact that was actively promoted including through television commercials.