World Aquatics

Men's ball: Circumference 68–71 cm (26.8–28 in), weight 400–450 g (14.1–15.9 oz); Women's ball: Circumference 65–67 cm (25.6–26.4 in), weight 350–400 g (12.3–14.1 oz); Waterproof, non-absorbent outer surface with a textured grip coating

Each team wears distinctly colored caps: one team wears white, the other dark blue (or contrasting dark color); Goalkeepers wear red caps, numbered #1 (starting goalkeeper) or #13 (reserve goalkeeper); Field players numbered 2–13 (excluding 1 and 13 for non-goalkeepers)

Width: 3 m (9.84 ft) between the inner edges of the goalposts; Crossbar underside: 0.90 m (2.95 ft) above the water surface when water depth is 1.50 m (4.92 ft) or more; 2.40 m (7.87 ft) from the bottom when depth is less than 1.50 m; Goals may be rigid (anchored to the pool deck or wall) or floa...

Swimwear: Non-transparent, one-piece or two-piece swimsuit (no body suits extending past shoulders or knees); Mouthguards: Recommended but not mandatory under World Aquatics rules; No jewelry, watches, or hard accessories permitted

Men’s field: 30 m × 20 m (98.4 ft × 65.6 ft) for FINA/World Aquatics and Olympic competitions; Women’s field: 25 m × 20 m (82 ft × 65.6 ft) for FINA/World Aquatics and Olympic competitions; Domestic and junior competitions may use shorter fields (minimum 20 m × 10 m)

2 m line (red/red markers): Marks the zone in front of each goal; ordinary fouls by the attacking team inside this area result in a free throw at the 2 m line; 5 m line (yellow markers): Penalty throw line; also defines the zone where exclusion fouls that prevent probable goals are upgraded to pe...

Visible shot clock (30-second countdown) displayed on both sides of the pool; Game clock showing actual playing time per period; Electronic scoreboard visible to teams, officials, and spectators

In the water: 7 players per team (6 field players + 1 goalkeeper); Roster: Maximum 13 players per team (11 field players + 2 goalkeepers); A team must have at least 7 players to start a match

Unlimited substitutions permitted, but only from the re-entry area during a dead-ball situation or after a goal; Flying substitutions (during play) allowed only at the re-entry area; the departing player must fully leave the water before the substitute enters; Goalkeeper-to-goalkeeper substitutio...

Center forward (hole set / 2-meter player): Positions directly in front of the opposing goal at the 2 m line; primary target for entry passes; Center back (hole-D): Defends the center forward; physical, pressing defense; Wings: Position at the sides of the attacking formation; drive and shoot fro...