At FINA, the event is called the 5K Team Event or the 5K Team Time Trial. In the race, there are three athletes per team and both genders must be represented (i.e., 2 men + 1 woman or 1 man + 2 women). The athletes start together and swim closely to one another throughout the race in order to gain the advantage of drafting, positioning, navigating and pacing. The most experienced teams swim and finish together in a tight formation after starting off in a staggered start. The 15 national teams at the 2011 FINA World Championships will start off in 1-minute intervals. The closer and straighter the teams swim on the 2-loop 5K course, the faster they will generally be, although there are no rules that specify how far apart the swimmers can be.
The final time is the time that the last (third) swimmer crosses the finish line. Despite the staggered start, it is possible that some teams will overtake other teams. All the standard rules of competition apply and referees are on the course to monitor sportsmanlike conduct. They are empowered to give yellow and red cards in the case there is cheating or impeding the progress of another team.
General Rules of Open Water Team Pursuit