In the swim leg of the Olympic triathlon, competitors may use any stroke to propel themselves through the water. Competitors may stand on the bottom or rest by holding an inanimate object, such as a buoy or stationary boat, but may not use either to gain an advantage. In an emergency, a competitor can call for assistance by raising an arm overhead. Once assistance is given, the competitor must retire from the race. Triathletes are allowed to wear wetsuits during the swim leg only if the water temperature is 20 degrees Celsius (68 degrees Fahrenheit) or lower. Wetsuits are mandatory in water colder than 14 degrees Celsius (57.2 degrees Fahrenheit).

In the bike leg of the Olympic triathlon, competitors are allowed to draft off of one another. Drafting occurs when a competitor rides directly behind another competitor--the rider in back feels less wind resistance and can thus maintain the same speed as the rider in front without using as much energy. Although drafting is allowed, competitors are not allowed to block out other riders. No forward progress is allowed without the bicycle. Competitors who appear to present a danger to themselves or others may be disqualified and removed from the competition by the race officials. Competitors may not ride the bike in the transition area. If a rider does not honor the mount line (where they must begin riding the bike) and the dismount line (where they must get off the bike), he or she is subject to a time penalty or disqualification.

In the run leg of the Olympic triathlon, competitors are allowed to walk but not crawl. Headphones and headsets are not permitted during competition. A competitor finishes the race when any part of the torso, excluding the head, neck, shoulders, arms, hips or legs, reaches the perpendicular line extending from the leading edge of the finish line.