A team's uniform consists of a jersey, shorts (or, in beach volleyball, a broader range of approved athletic wear suited to sand and sun), and matching socks, with each player wearing a clearly visible number on both the front and back of the jersey. Numbers must fall within a range set by the competition's rules, and the team captain typically wears a distinguishing mark on the jersey — often a stripe under the number — so officials can identify who holds that role during the match.
The one deliberate uniform exception in the sport is the libero, who is required to wear a jersey — or at minimum a contrasting vest or bib over a standard jersey at some levels — that is visibly different in color or design from the rest of the team's uniform. The rule exists purely for officiating and spectator clarity: because the libero is subject to unique positional and attacking restrictions, referees, opposing coaches and fans all need to be able to identify that player instantly during fast-moving play.
Beach volleyball's different uniform norms
Beach volleyball uniform rules are generally less restrictive than indoor rules given the outdoor, sand-court setting, though numbering and clear player identification requirements still apply at every sanctioned level of competition.
Why the contrast rule specifically protects officiating accuracy
The libero jersey rule is a good example of how volleyball's rulebook sometimes solves a tactical problem with a purely visual, non-athletic fix: rather than relying on referees, opposing coaches and scorers to memorize which roster number happens to be the libero on any given team, a clearly contrasting jersey lets everyone identify that player from across the court or from a broadcast camera at a glance, sharply reducing the chance of a missed or mistaken call on one of the sport's more heavily regulated positions.
