There are a number of rules that are different from normal HS play during Summer League. Each of these changes is designed to either allow for faster play or for the relaxed nature of summer league rosters.
Match Format - (see Summer League Format FAQ )
Uniforms - uniforms (or numbers) are not required, but are allowed.
Substitutions - "free" substitutions are allowed at all positions (similar to Libero) between points, unlimited substitutions are allowed - also, no libero tracking is enforced - please make your substitutions quickly. Players are still only allowed to substitute into one spot in the rotation per set.
Warmups - (see Summer League Format FAQ )
Referees - (see Summer League Format FAQ )
Playing on multiple teams - players from younger teams (first wave) are allowed to play up in the second wave. Multi-team programs should not have Varsity players playing with a younger team during the first wave. Please talk to the competition director if you have problems with the number of players available.
Rotation - overlapping rotation errors are not called during summer league, but teams must serve in rotation and should "attempt" to stay in full rotation.
Double contact - double contact calls against setters are less frequent (to allow for the limited practice time many teams have so early in their season), but are called when obvious.