A double bounce is an illegal movement during competition in the sport of springboard or platform diving that will result in the dive being declared a "fail dive."
Once a diver has left the springboard from one foot during the hurdle, they must land on the end of the board with two feet and then leave the springboard to begin their dive. If a diver lands back on the board in an attempt to bounce again and gain more height, the referee should declare a fail dive and the diver will receive zero points.
On platform, whether using a running forward approach or standing, the diver is also not allowed to bounce on the surface prior to the take-off and execution of the dive.
As a training technique, a double bounce (or triple bounce) is many times used in an effort to teach balance during the hurdle and approach and proper timing either over water or in a dryland setting.