In the men's tournament, there are 12 teams divided into two groups of six. Both groups play a round-robin style preliminary stage so that each team plays all five other teams in its group. Every win is worth two points for the overall group standings, and every tie is worth one point. Once all matchups have taken place, the top-four teams in each group’s standings advance to the knockout round, while the bottom two teams per group are eliminated. 

The women’s tournament is limited to 10 teams, divided into two groups of five. Each group plays a round robin and the last-place team in each group after all games have taken place is eliminated. The remaining eight teams compete in the knockout stage in the same format as the men’s tournament. 

Ties on points are common in this format, so the following tiebreakers are used to arrive at a final classification for each group. 

• The team that wins the game between the two tied teams is placed higher 
• If the game between them is a tie, whichever team fairs better against the highest-ranked team (considering goal difference) is placed higher. If that is not conclusive, the same principle is applied using the second-highest-ranked team. 
• If still tied, both teams contest a penalty shootout. 

In the quarterfinal round, the top team from Group A plays the fourth-ranked team in Group B, and so on. Ties are decided by penalty shootout and single-elimination rules apply. The winner of each quarterfinal matchup advances to the semifinal round. Quarterfinal losers play against each other to determine 5th-8th place. The winners of the semifinal games advance to the gold-medal game, while the losers play for bronze. 

Olympic water polo matches consist of four, eight-minute quarters. However, due to the clock stopping when the ball is not in play, a quarter typically lasts around 12 minutes — meaning a game usually lasts between approximately 40-50 minutes. 

Players score in Olympic water polo by throwing the ball completely past the goal line of the opponent's goal. Each goal is worth one point. A ball can also be pushed passed the face of the goal to score a point. 

Due to the size of the pool used in Olympic water polo, players tread water the entire game and are not allowed to touch the bottom or sides of the pool. Only the goalkeeper is allowed to touch the sides of the pool and can handle the ball with only one hand.