There are seven players in the water from each team at one time. There are six players that play out and one goalkeeper. Unlike most common team sports, there is little positional play; field players will often fill several positions throughout the game as situations demand. These positions consist of the center (or hole set), the point (who also usually plays center back or hole defender), the two wings and the two flats. Players who are skilled in all of these positions on offensive or defensive are called utility players. Utility players tend to come off of the bench, though this is not absolute. Certain body types are more suited for particular positions, and left-handed players are especially coveted on the right-hand side of the field, allowing teams to launch 2-sided attacks.
The offensive positions include: one center (a.k.a. two-meter offense, 2-meters, hole set, set, hole man, bucket, pit player or pit-man), two wings (located on or near the 2-meter), two drivers (also called "flats," located on or near the 5-meter), and one "point" (usually just behind the 5 meter), positioned farthest from the goal. The wings, drivers and point are often called the perimeter players; while the hole-set directs play. There is a typical numbering system for these positions in U.S. NCAA men's division one polo. Beginning with the offensive wing to the opposing goalies right side is called one. The flat in a counter clockwise from one is called two. Moving along in the same direction the point player is three, the next flat is four, the final wing is five, and the hole set is called six.
The most basic positional set up is known as a 3–3, so called because there are two lines in front of the opponent's goal. Another set up, used more by professional teams, is known as an "arc," umbrella, or mushroom; perimeter players form the shape of an arc around the goal, with the hole set as the handle or stalk. Yet another option for offensive set is called a 4–2 or double hole; there are two center forward offensive players in front of the goal. Double hole is most often used in "man up" situations, or when the defense has only one skilled hole D, or to draw in a defender and then pass out to a perimeter player for a shot ("kick out").
The center sets up in front of the opposing team's goalie and scores the most individually (especially during lower level play where flats do not have the required strength to effectively shoot from outside or to penetrate and then pass to teammates like the point guard in basketball). The center's position nearest to the goal allows explosive shots from close-range ("step-out" or "roll-out", "sweep," or backhand shots).
Another, albeit less common offense (violation), is the motion offense in which two "weak-side" (to the right of the goal for right-handed players) perimeter players set up as a wing and a flat. The remaining four players swim in square pattern in which a player swims from the point to the hole and then out to the strong side wing. The wing moves to the flat and the flat to the point. The weak side wing and flat then control the tempo of play and try to make passes into the player driving towards the center who can then either shoot or pass. This form of offense is used when no dominate hole set is available, or the hole defense is too strong. It is also seen much more often in women's water polo where teams may lack a player of sufficient size or strength to set up in the center. The best advantage to this system is it makes man-coverage much more difficult for the defender and allows the offense to control the game tempo better once the players are "set up." The main drawback is this constant motion can be very tiring as well as somewhat predictable as to where the next pass is going to go.
Defensive positions are often the same positions, but just switched from offense to defense. For example, the center forward or hole set, who directs the attack on offense, on defense is known as "hole D" (also known as set guard, hole guard, hole check, pit defense or two-meter defense), and guards the opposing team's center forward (also called the hole). Defense can be played man-to-man or in zones, such as a 2–4 (four defenders along the goal line). It can also be played as a combination of the two in what is known as an "M drop" defense, in which the point defender moves away ("sloughs off") his man into a zone in order to better defend the center position. In this defense, the two wing defenders split the area furthest from the goal, allowing them a clearer lane for the counter-attack if their team recovers the ball.
The goalkeeper is generally one of the more challenging positions not only in the sport of water polo, but in any sport. A goalie has to be able to jump out of the water, using little more than one's core and legs, and hold the vertical position without sinking into the water, all while tracking and anticipating a shot. The goal is 2.8 m2 in face area; the goalie should also be a master of fast, effective lateral movement in the water as well as lightning fast lunges out of the water to block a shot. Another key job that the goalkeeper is responsible for is guiding and informing his or her defense of imposing threats and gaps in the defense, and making helpful observations to identify a gap in the defense that the defenders may or can not see. The goalkeeper is also the "quarterback", as he or she usually begins the offensive play. It is not unusual for a goalie to make the assisting pass to a goal on a break away.
The goalkeeper is given several privileges above those of the other players, but only if he or she is within the five meter area in front of his or her goal:
- The ability to punch the ball with a clenched fist.
- The ability to touch the ball with two hands.
- The ability to touch the bottom of the pool. (Pool depth permitting - most competitions state the pool has to be at least 2 meters deep)
In general, a foul that would cause an ejection of a field player might only bring on a five meter shot on the goalie. The goalkeeper also has one limitation that other players do not have: he or she cannot cross the half-distance line. Also, if a goalie pushes the ball under water, it is not a turnover like with field players. It is a penalty shot, also called a 5-meter shot, or simply, a "5-meter"