Ironman vs T100: how the two race series compare
Ironman and T100 are two different ways to race a long triathlon. Ironman is a global series of half and full distance races with a World Championship in Kona. T100 is a 100 km format run by the Professional Triathletes Organisation (PTO) with World Triathlon, and it also has age-group racing. This guide compares distances, qualification, costs and which one may suit you.
Open the Triathlon Pace CalculatorThe short answer
Choose Ironman if you want the classic half or full distance and the biggest choice of races around the world. Choose T100 if you want a shorter, faster 100 km race, the same distance the professional T100 tour races, and a different route to a world championship. Both are non-drafting, and age-groupers can race both.
Distances and format
| Format | Swim | Bike | Run | Total |
|---|---|---|---|---|
| T100 (100 km) | 2 km | 80 km | 18 km | 100 km |
| Ironman 70.3 | 1.9 km | 90 km | 21.1 km | 113 km |
| Ironman (full) | 3.8 km | 180 km | 42.2 km | 226 km |
The T100 distance sits between Olympic and 70.3. It is a little shorter than a 70.3 but with a longer swim and a shorter run. A full Ironman is a very different challenge: most age-groupers take roughly 11 to 17 hours, and the overall course cut-off is 17 hours.
Who races
Both series have a professional side and an age-group side. In 2026 the T100 tour has nine events ending with a World Championship Final in Qatar in December. Professional women and men race on separate weekends instead of together, and each race has a 275,000 USD prize fund, with a 1.45 million USD series prize pool.
Age-group racing accompanies nearly every stop. The 100 km distance is available at Gold Coast, Singapore, Spain, London, Vancouver and Dubai, while the French Riviera and San Francisco stops use partner races (Saint-Raphael Triathlon and Escape from Alcatraz).
Ironman runs 170+ races worldwide, including the Pro Series for professionals, and the 2026 World Championship returned to Kona on 10 October 2026, with women and men racing on the same day.
Qualification: Kona slots vs T100 World Championship
| Ironman | T100 | |
|---|---|---|
| Championship | IRONMAN World Championship (Kona in 2026), and a separate 70.3 World Championship | T100 Age-Group World Championship (Qatar, December 2026) |
| How you qualify | At qualifying events: the age-group winner earns an automatic slot, and the rest go to a performance pool ranked by your time against an age-group standard, with roll-down | Finish top 10 in your age group and gender at any T100 mass participation race, or be selected by your national federation |
| Roll-down | Yes, through the performance pool | No, unclaimed places are not rolled down |
| Extra requirements | Accept your slot and register on time | National federation endorsement and national race suit required |
| Entry fee | Race entry plus championship entry | 595 USD for the championship (2026) |
Neither series awards points to age-groupers for qualification. Both use slots. Rules change between seasons, so check the organiser's page for the current cycle before planning around a slot.
Costs
Reported 2026 entry fees for Ironman are roughly 800 to 975 USD for a full distance and 375 to 450 USD for a 70.3, and some events are higher, particularly in Europe. T100 mass participation fees vary by event, so check the race page. In both cases, entry is only part of the cost. Travel, accommodation, bike transport, nutrition and equipment often cost more than the entry fee.
Training and pacing differences
- T100 rewards speed over a shorter distance. The total distance is shorter than a 70.3, so the pacing is typically more aggressive, but practise the effort you plan to hold before race day.
- A 70.3 needs a disciplined bike effort so you can run a half marathon well. The 70.3 pacing guide covers this.
- A full Ironman needs much more volume and fuelling discipline. Plan nutrition early and practise it in training.
- If you are stepping up from Olympic distance, a T100 or a 70.3 is a natural next step before a full.
Use the Triathlon Pace Calculator with a custom course of 2 km, 80 km and 18 km to set splits for a T100, or choose Half / 70.3 or enter your own full-distance values.
Which should you choose?
- Pick Ironman 70.3 if you want the most races to choose from and a long-established half-distance format.
- Pick T100 if you want a faster 100 km race, to race the professional distance, or to chase the T100 Age-Group World Championship.
- Pick a full Ironman if the 226 km challenge and Kona are the goal, and you can commit the training time.
- Check dates, location and cut-offs on the official event pages before registering, because calendars and rules change each season.
FAQ
What is the T100 distance?
A T100 is a 100 km triathlon: 2 km swim, 80 km bike and 18 km run.
Is T100 harder than a 70.3?
It is shorter (100 km against 113 km), so the total effort is lower, but you will usually race at a higher intensity. Pace it with the same discipline as any non-drafting race.
Can age-groupers race T100?
Yes. Age-group racing takes place at most T100 stops, with the 100 km distance at several of them.
How do I qualify for the T100 Age-Group World Championship?
Finish in the top 10 of your age group and gender at a T100 mass participation race, or be selected through your national federation. National federation endorsement is needed to confirm your entry.
How do I qualify for Kona?
You earn a slot at an Ironman qualifying event, either as an age-group winner or through the performance pool based on your time relative to an age-group standard. Check the current slot allocation on ironman.com.