What is a triathlon? Format, distances, how it works

How a triathlon works

You swim, then run to your bike (transition 1, "T1"), then cycle, then change shoes (T2), then run. The clock never stops. T1 and T2 are part of your finish time, so they are short — 30 to 90 seconds for experienced racers.

You race against your own clock, but you also race against everyone else on the course. Drafting on the bike is illegal in most amateur races (you must keep ~10 m of distance from the rider in front), so the bike leg is genuinely an individual time trial.

Distances

Four official distances: sprint (750 m / 20 km / 5 km), olympic (1.5 km / 40 km / 10 km), half-ironman or 70.3 (1.9 km / 90 km / 21.1 km), and full ironman (3.8 km / 180 km / 42.2 km).

Beyond the standard four, you will see super-sprint races (375 m / 10 km / 2.5 km) for first-timers, and ultra-distance triathlons that exceed ironman.

Equipment basics

You need a bike (any type — many first-timers race a road or hybrid bike), goggles, a tri-suit (worn through all three legs), and running shoes. Wetsuits are usually mandatory below 22 °C water and forbidden above 24 °C.

You do not need a triathlon-specific bike for sprint or olympic distance. A standard road bike with clip-on aero bars is more than enough until you are racing 70.3 or longer.

Where to start

Pick a sprint-distance race with a pool swim, not an open-water swim. Open water is a different skill (sighting, mass starts, navigation) and is harder to learn cold. After one or two pool sprints, move to open-water sprint, then olympic.