Bouncy castles are generally designed and intended for use by children. The recommended age for playing on a bouncy castle varies depending on the specific castle's size and design, as well as the manufacturer's guidelines. However, most bouncy castles are suitable for children aged 3 to 12 years old.

Younger children, typically aged 3 to 5, may require closer adult supervision and assistance while playing on a bouncy castle due to their smaller size and less-developed coordination. It's important to ensure that younger children are accompanied by an adult to ensure their safety and to help them navigate the bouncy castle.

Older children, between the ages of 6 and 12, can generally play more independently on a bouncy castle. However, adult supervision is still recommended to ensure their safety and to prevent rough or unsafe play.

It's crucial to consider the size and weight limits specified by the manufacturer to ensure that children are using the bouncy castle within the recommended guidelines. This helps prevent overcrowding and reduces the risk of accidents or injuries.

Ultimately, the decision on the appropriate age for children to play on a bouncy castle should be based on the individual child's development, physical abilities, and the specific guidelines provided by the manufacturer or event organizer.