Effects of a constant time delay procedure on the Halliwick's method of swimming rotation skills (i.e., vertical and lateral rotation) for children with autism were investigated. A single subject multiple baseline model across behaviors with probe conditions was used. Participants were three boys, 8-9 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 rotation skills significantly during intervention. In addition, subjects maintained their successful skills during first, second and fourth week of generalization phases. Results showed that constant time delay was an effective way of increasing and maintaining Halliwick's method of swimming rotation skills of children with autism. (Contains 3 tables and 2 figures.)