The events in any competition may have only one of the four major styles or a combination of all the four styles in a fixed order.
Competitions are held in each of the major four swimming styles. At the Olympics five events are conducted under free style. They are 50 meter, 100 meter, 200 meter, 400 meter, 1500 meter for men and 50 meter, 100 meter, 200 meter, 400 meter, and 800 meter for women. Two events, 100 meter and 400 meter are also conducted under all the other three styles, breaststroke, butterfly and backstroke, for both men and women.
Individual medley competitions are also held at various tournaments. In these competitions a single swimmer swims a quarter of the track distance in each of the four styles in the same race. At the Olympics, 200 and 400 meter individual medleys are conducted for both men and women. The swimmer swims butterfly, backstroke, breaststroke and finally freestyle in the same order in these medley events.
Other kinds of individual medley races of 100 meters, are conducted in other nonOlympics swimming championships. The swimmer should swim at least four strokes in each of the styles. So, the course length cannot be made any shorter.
Relay events are group events. Each country or team participating in the event forms a group of four swimmers. Each swimmer swims a quarter of the track distance. The fastest swimmer is usually placed at the end. The team spirit in a group event usually makes swimmers swim faster than individual races. Relay events can be both freestyle and medley. In a freestyle relay each swimmer swims in any style other than backstroke, breaststroke and butterfly. In a medley relay each swimmer swims a quarter of the total course length in a different style in the order Backstroke, Breaststroke, Butterfly and Freestyle. A 4 × 100 meter freestyle relay, a 4 × 200 meter freestyle relay and a 4 × 100 meter medley relay events are part of swimming competitions at the Olympics.
Long distance free style marathons are conducted in large open water bodies like lakes, rivers and oceans. Swimmers are free to use any style in these events. However, most swimmers across the globe use front crawl in these competitions.
Since 2008, a 10 km open water swimming championship is a part of the Olympics. FINA also organizes other open marathon events of 5km, 10 km and 15 km at world aquatic championships, held once in every two years.
Following are the swimming events held at the Olympics 2012 −