Triathlon Race Distances

The origins of triathlon

Triathlon was invented in 1974 in San Diego as an alternative endurance workout for runners. The first event was a 6-mile run, 5-mile bike and 500-yard swim across Mission Bay.

From Hawaii to the Olympics

The Ironman was born in 1978 when Navy Commander John Collins merged three existing Hawaiian races: the Waikiki Roughwater Swim (3.86km), the Around-Oahu Bike Race (185km) and the Honolulu Marathon (42.2km). His brief: "Whoever finishes first, we'll call him the Iron Man."

The ITU (now World Triathlon) was founded in 1989 and standardised the Olympic distance at 1,500m/40km/10km. Triathlon debuted at the Sydney Olympics in 2000.

The name "70.3" refers to the total miles in a Half Ironman: 1.2 miles swim + 56 miles bike + 13.1 miles run = 70.3 miles.

Which distance is right for you?

Most triathletes progress through distances over several seasons. Here is the typical progression and what to expect at each level.

Sprint (750m/20km/5km)

The best starting point. 8–12 weeks of 3× per week training is sufficient. Finish times of 1:30–2:00 for beginners. High-intensity racing that rewards speed over pacing strategy.

Olympic (1.5km/40km/10km)

The standard benchmark distance. Requires 4–5 months of structured training. Tests your ability to pace all three disciplines — too hard on the bike and the run falls apart.

70.3 / Half Ironman (1.9km/90km/21km)

A major undertaking requiring 6+ months of training and careful nutrition planning. First-timers should have at least two sprint or olympic races under their belt.

Full Ironman (3.8km/180km/42.2km)

The ultimate endurance challenge. Plan for 9–12 months of dedicated training, with peak weeks reaching 15–20 hours. Nutrition and pacing strategy are as important as fitness.

Age is not a barrier — athletes in their 60s and 70s regularly complete Ironman races. Training quality matters more than training volume for age-groupers.

How a triathlon course is structured

All triathlons follow swim → transition 1 (T1) → bike → transition 2 (T2) → run, in that order. The transition area is the hub connecting all three disciplines.

Swim course

Usually a looped open-water course (lake, river, sea) marked by buoys. Waves start every 3–5 minutes by age group. Wetsuits permitted in most events below 24°C.

Bike course

Road closed to traffic (elite) or open with marshals (age-group). One or multiple loops. Drafting is legal in ITU/World Triathlon events but illegal in IRONMAN events.

Run course

Usually a flat or gently rolling out-and-back or loop course. For Ironman, multiple run loops allow athletes to see and hear the finish line repeatedly — powerful motivation.

Transition area

Your bike is racked here with your helmet, shoes, and run gear. Your transition spot is allocated by race number. Set up systematically and memorise landmarks near your rack.

Transition times count in your official finish time. A well-practised T1 and T2 can save 2–4 minutes over a race — equivalent to a significant improvement in any single discipline.