All triathlons are not created equal. Races are broken down into four basic distances, with courses and culture making each one a unique challenge. In this blog I have aimed to do a list with approximate guidelines for the four distances — your triathlon might be slightly shorter or longer, but this is a good general guide.
Triathlon Types and Distances
0.5km to 0.75km swim (0.3 to 0.5 mile), 20km to 22km bike (12.4 to 13 miles), and 5km run (3.1 miles). Super sprints are slightly shorter races: 0.4km swim (0.25 mile), 10km bike (6.2 miles) and 2.5km run (1.5 miles). The sprint is the most popular distance in the sport. Beginning triathletes most often select sprint distances as their first events.
1.5km swim (0.9 mile), 40km bike (24.9 miles), and 10km run (6.2 miles). The official distance of the Olympic event, this event requires a good fitness base.
1.9km swim (1.2 miles), 90km bike (55.9 miles), and 21km run (13 miles). Half Iron events are far more challenging than the shorter distances and sometimes are used as qualifiers for Ironman triathlons. Don't attempt a race at this distance until you've competed in sprint or Olympic events.
3.8km swim (2.4 miles), 180km bike (111.8 miles), and 42km run (26.2 miles — a marathon). Each of the legs alone in this event challenges even the experienced endurance athlete. Train for an Ironman distance only after you've had experience in shorter races and completed at least one Half Iron.