Play buses are specially converted for their purpose, usually from second hand vehicles, although occasionally are purpose built by a bus manufacturer.
Play buses can be of any size, from minibuses to double-deckers, and may be operated by charities, education authorities or as private businesses.
The latter particularly market their services as a mobile party venue for children's birthday celebrations and the like.
Depending on usage and fittings, play buses may provide mobile playgrounds, gymnasiums, library services, or education centres as a mobile classroom.
In the United Kingdom, the National Playbus Association is a charity that provides support and advice to organisations, wishing to operate play buses.