The rules have changed over the years and we will endeavour to keep you up to date. These are the rules according to the International swimming body FINA.
1. During the start and turn you are able to take 1 full arm stroke that where the hands can be pulled all the way to the thighs underwater. During the arm stroke, 1 butterfly kick may be completed and then a breaststroke kick may be completed. All of this can be done underwater.
2. From the moment you leave the wall for a start or turn you must be on your front. At no point are you to rotate on your back.
3. For each stroke you must perform 1 arm stroke and 1 leg kick in that order. The 2 arms and legs must perform the same motion at the same time.
4. You cannot bring the hands past the hipline except in the start and turn.
5. The hands can be brought forward under or over the water. The elbows must not be above the surface of the water except for the final stroke into a turn or finish.
6. During each stroke, part of the head must break the surface of the water. The head must break the surface of the water by the time the hands reach their widest point on the second stroke from a start or turn (the 1st stroke is the one completed under water from the start or turn)
7. The feet must be turned outwards during the propulsion part of the kick. You cannot have a scissor, flutter or dolphin kick and the legs must be simultaneous.
8. The feet can break the surface of the water as long as there is no down kick
9. You must touch the wall with both hands during a turn or finish
Federation Internationale de Natation (FINA) – www.fina.org