Effects of a constant time delay procedure on aquatic play skills of children with autism was investigated. A single subject multiple probe model across behaviors with probe conditions was used. Participants were four boys, 7-9 years old. Data were collected over a 10-week period using the single opportunity method as an intervention. Results revealed that all subjects increased their correct target skills significantly during intervention. In addition, subjects maintained their successful play skills during first, second and forth week of maintenance phases. Results showed that constant time delay was an effective way of increasing and maintaining aquatic play skills of children with autism. (Contains 2 tables and 4 figures.)