- The modern game originated as a form of rugby football played in rivers and lakes in England and Scotland with a ball constructed of Indian rubber. This "water rugby" came to be called "water polo" based on the English pronunciation of the Balti word for ball, pulu.
- The rules of water polo were originally developed in the late nineteenth century in Great Britain by William Wilson.
- To deal with variations in regional rules, in 1888, the London Water Polo League was founded and approved a set of rules to allow team competition, forming the basis of the present game. The first English championships were played in 1888. In 1890, the first international water polo game was played; Scotland defeated England, 4-0.
- The annual Varsity Match between Oxford and Cambridge Universities is the sport's longest running rivalry, first played in 1891.
- Men's water polo at the Olympics was the first team sport introduced at the 1900 games, along with cricket, rugby, soccer, polo (with horses), rowing and tug of war.
- Between 1890 and 1900, the game developed in Europe, with teams competing in Germany, Austria, France, Belgium, Hungary and Italy, using British rules. A different game was being played in the United States, characterized by rough play, holding, diving underwater, and soft, semi-inflated ball that could be gripped tightly and carried underwater. As a result, European teams did not compete in the 1904 Olympic championships in St. Louis. By 1914, most US teams agreed to conform to international rules. An international water polo committee was formed in 1929, consisting of representatives from Great Britain and the International Amateur Swimming Federation (FINA). Rules were developed for international matches and put into effect in 1930; FINA has been the international governing body for the sport since that time.
- Women's water polo became an Olympic sport at the 2000 Sydney Olympic Games after political protests from the Australian women's team.
- Every two to four years since 1973, a men's Water Polo World Championship is organized within the FINA World Aquatics Championships. Women's water polo was added in 1986. A second tournament series, the FINA Water Polo World Cup, has been held every other year since 1979. In 2002, FINA organized the sport's first international league, the FINA Water Polo World League.
- Over the years, both technical and rule changes affected the character of the game. In 1928, Hungarian water polo coach Bela Komjadi invented the "air pass," or "dry pass", a technique in which a player directly passes the ball through the air to another player, who receives it without the ball hitting the water. Previously, players would let the ball drop in the water first and then reach out for it, but the dry pass made the offensive game more dynamic, and contributed to Hungarian dominance of water polo for 60 years. In 1936, James R. ("Jimmy") Smith, California water polo coach and author of several books on water polo mechanics, developed a water polo ball made with an inflatable bladder and a rubber fabric cover, which improved performance. The previous leather ball absorbed water and became heavier during the game. In 1949, rule changes allowed play to continue uninterrupted after a referee whistled an ordinary foul, speeding up play. In the 1970s, the exclusion foul replaced a point system for major fouls; players guilty of this foul were excluded for a 1 minute penalty and their team forced to play with fewer players. Possession of the ball was limited to 45 seconds before a scoring attempt. Time of penalties and possession have been reduced since then. The direct shot on goal from the seven (7) meter line after a free throw was allowed in 1994, and changed to a five meter throw in 2005.
- There are six field player positions and a goalkeeper on each team. Unlike most common team sports, there is not any positional play; field players often will fill several positions throughout the game as situations demand. Players who are skilled at several offensive or defensive roles are called utility players. Utility players tend to come off of the bench, though this isn't absolute. Certain body types are more suited for particular positions, and left-handed players are especially coveted, allowing teams to launch 2-sided attacks.
- The offensive positions include: 1 center (a.k.a. hole set, 2-meter offense, pit player or pit-man), 2 wings, 2 drivers (also called "flats"), and 1 "point" man. The hole set directs the attack, and on defense is known as hole check, hole D, pit defense or 2-meter defense, defending the opposing team's center forward. The wings, drivers and point are often called the perimeter players. The most basic positional set up is known as a 3-3, due to the fact that there are two lines both containing 3 players. Another set up, used more by professional teams, is known as an "arc", umbrella, or mushroom, because the perimeter players form the shape of an arc, umbrella or mushroom around the goal with the center forward as the handle or stalk. The center forward, known by players as hole set or 2-meter is the center player in the middle of the umbrella who is closest to the opposing teams goal. This player sets up in front of the opposing team's goalie and usually scores the most individually (especially during lower level play where arc or perimeter players do not have the required leg strength to drop effectively onto the pit player) or contributes most often to initiating plays. The five perimeter players often swim the most and interchange their positions several times during a single offensive play. They contribute to the actual execution of plays, and cumulatively score the most points for the team. The point player's position provides opportunities to pass to teammates and communicate among the offense, like the point guard in basketball. The center forward also plays a big role offensively because they sit closest to the goal and usually attempt to shoot from close-range as frequently as possible with "Step-out"(a.k.a Roll-out), "Sweep", or "Backhand" shots.
- 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 goal:
* The ability to touch the ball with two hands.
- Not all water polo rules are the same. For example, overtime is different on the international level and in college. In FINA (international) rules, if the score is tied at the end of regulation play, two overtime periods of three minutes each are played. If the tie is not broken after two overtime periods, a penalty shootout will determine the winner, much like in hockey. Five players and a goalkeeper are chosen by the coaches of each team. Players shoot from the 5 meter line alternately at either end of the pool in turn until all five have taken a shot. If the score is still tied, the same players shoot alternately until one team misses and the other scores. Overtime periods are common in tournament play due to the high level of skill of these superior teams; Team USA defeated Hungary in the 2004 Women's Water Polo World League Super Final when US goalie Jackie Frank made 2 stops on penalty shots.
- Differing from FINA rules, overtime in American college varsity water polo play is sudden victory, first team to score wins, after the two three minute overtime periods. There are no shootouts, the overtimes simply continue until a team scores.
- All water polo is not the same, either, as the game has developed into different variations.
- Inner tube water polo is a style of water polo with the important difference that players, excluding the goalkeeper, are required to float in inner tubes. By floating in an inner tube players expend less energy than traditional water polo players, not having to tread water. This allows casual players to enjoy water polo without undertaking the intense conditioning required for conventional water polo. This sport is predominantly played at universities/colleges by intramural coed teams. The sport's rules resemble those of water polo, however, with no governing body the rules vary across different leagues. For example, while the winner is determined by the team which scores the most goals, some leagues award one point for a male goal, and two points for a female goal, while others award one for either. The game was invented in 1969 by now retired UC Davis associate athletic director of intramural sports and sport clubs, Gary Colberg. Noticing how much fun the water polo team was having, Mr. Colberg thought up the idea of using tubes so that people with no experience in water polo could still enjoy the game.
- Surf polo, another variation of water polo, is played on surfboards. First played on the beaches of Waikiki in Hawaii in the 1930s and 1940s, it is credited to Louis Kahanamoku, Duke Kahanamoku's brother.
- Canoe Polo or kayak polo is one of the eight disciplines of canoeing pursued in the UK, known simply as "polo" by its aficionados. Polo combines paddling and ball handling skills with an exciting contact team game, where tactics and positional play are as important as the speed and fitness of the individual athletes.
- Water polo is a team water sport requiring an ability to swim. Field players must swim end to end of a 30-meter pool non-stop many times during a game without touching the sides or bottom of the pool. The front crawl stroke used in water polo differs from the usual swimming style in that water polo players swim with the head out of water at all times to observe the field. The arm stroke used is also a lot shorter and quicker and is used to protect the ball at all times. Backstroke is used by defending field players to track advancing attackers and by the goalie to track the ball after passing. Water polo backstroke differs from swimming backstroke; the player sits almost upright in the water, using eggbeater leg motions with short arm strokes to the side instead of long straight arm strokes. This allows the player to see the play and quickly switch positions. It also allows the player to quickly catch an on coming pass with a free hand.
- As all field players are only allowed to touch the ball with one hand at a time, they must develop the ability to catch and throw the ball with either hand and also the ability to catch a ball from any direction, including across the body using the momentum of the incoming ball. Experienced water polo players can catch and release a pass or shoot with a single motion.
- The most common form of water treading is generally referred to as "egg-beatering" named because the circular movement of the legs resembles the motion of an egg-beater. Egg beater is used for most of the match as the players cannot touch the bottom of the pool. The advantage of egg-beater is that it allows the player to maintain a constant position to the water level, and uses less energy than other forms of treading water such as the scissor kick, which result in the player bobbing up and down. It can be used vertically or horizontally. Horizontal egg-beater is used to resist forward motion of an attacking player. Vertical eggbeater is used to maintain a position higher than the opponent. By kicking faster for a brief period the player can get high out of the water (as high as their suit—below their waistline) for a block, pass, or shot.
- In 1999, the Peter J. Cutino Award was established by the San Francisco Olympic Club, and is presented annually to the top American male and female collegiate water polo player.
- Musician Sean Paul is a former member of Jamaica's national water polo team.
- Former major league baseball commissioner and US Olympic Committee chair Peter Ueberroth was a water polo player at San Jose State.
- Prince William of England was the captain of his collegiate water polo team at St Andrew's University, Scotland.
- Captain Jonathan Archer (played by actor Scott Bakula), a fictional character in the television series Star Trek: Enterprise, played water polo for Stanford University and competed in the 2134 North American Water Polo Regionals against Princeton University.