Water polo is a team water sport. The game consists of 4 quarters (or periods) in which the two teams attempt to score goals by throwing the ball into their opposition's goal, with the team that scores the most goals winning the game.
A team consists of 6 field players and one goalkeeper in the water at any one time. In addition to this, teams may have substitute players (up to six under most governing bodies), including up to one substitute goalkeeper.
Water polo is typically played in an all-deep pool (usually at least 1.8m deep), and players need considerable stamina and endurance to play the game.