Ironman
Ironman Triathlon
An Ironman is the ultimate triathlon challenge: 3.8km swim, 180km bike, 42.2km marathon run. Learn what it takes to complete an Ironman, typical times, and training requirements.
Quick Answer
Ironman — An Ironman is a full-distance triathlon consisting of a 3.8km (2.4mi) swim, 180km (112mi) bike, and a full 42.2km (26.2mi) marathon run. It's widely considered one of the most challenging single-day endurance events in the world, with finish times typically ranging from 8-17 hours.
Ironman Distances
| Discipline | Distance (Metric) | Distance (Imperial) |
|---|---|---|
| Swim | 3.8km | 2.4 miles |
| Bike | 180km | 112 miles |
| Run | 42.2km | 26.2 miles (marathon) |
| Total | 226km | 140.6 miles |
Ironman Finish Times
| Level | Swim | T1 | Bike | T2 | Run | Total |
|---|---|---|---|---|---|---|
| Beginner | 1:20-1:40 | 10-15 min | 7:00-8:00 | 8-12 min | 5:00-6:30 | 14:00-17:00 |
| Intermediate | 1:05-1:20 | 6-10 min | 5:45-6:30 | 5-8 min | 4:15-5:00 | 11:30-14:00 |
| Advanced | 55-65 min | 4-6 min | 5:00-5:30 | 3-5 min | 3:30-4:15 | 10:00-11:30 |
| Elite | 45-52 min | <3 min | 4:10-4:30 | <2 min | 2:45-3:15 | 8:00-9:15 |
| Pro | 45-50 min | <2 min | 4:00-4:20 | <1 min | 2:35-2:55 | 7:40-8:15 |
Use our Ironman Calculator for personalized pace predictions.
The Ironman History
| Year | Milestone |
|---|---|
| 1978 | First Ironman in Hawaii (15 finishers) |
| 1981 | Moved to Kona, Hawaii |
| 1982 | Julie Moss crawls to finish line |
| 2000s | Global expansion |
| Today | 40+ Ironman races worldwide |
The Ironman World Championship in Kona, Hawaii remains the sport's ultimate prize.
Training for Ironman
Time Commitment
| Goal | Training Hours/Week |
|---|---|
| Finish | 12-15 hours |
| Competitive | 15-20 hours |
| Kona qualification | 18-25 hours |
Training Timeline
| Phase | Duration | Focus |
|---|---|---|
| Base | 12-16 weeks | Aerobic foundation |
| Build | 10-12 weeks | Volume and intensity |
| Peak | 4-6 weeks | Race-specific, long efforts |
| Taper | 2-3 weeks | Rest and recovery |
Total: 30-40 weeks of dedicated training.
Sample Peak Training Week
| Day | Workout | Duration |
|---|---|---|
| Monday | Swim + strength | 90 min |
| Tuesday | Run | 90 min |
| Wednesday | Bike | 2.5-3 hours |
| Thursday | Swim + run brick | 2 hours |
| Friday | Easy swim or rest | 45 min |
| Saturday | Long bike + brick run | 5-7 hours |
| Sunday | Long run | 2-2.5 hours |
Read our Ironman Pacing Strategy guide.
Race Day Strategy
Swim (3.8km)
| Strategy | Target |
|---|---|
| Effort | 70-75% (very controlled) |
| Pacing | Even splits |
| Focus | Relaxation, sighting |
| Mindset | Just the warm-up |
Bike (180km)
This is where Ironman is won or lost:
| Strategy | Target |
|---|---|
| Effort | Stay below FTP |
| Power | 70-75% FTP for age-groupers |
| Nutrition | 60-90g carbs/hour |
| Hydration | 500-1000ml/hour |
Common mistake: Going too hard on the bike. If you feel great at mile 80, you're going too hard.
Run (42.2km)
| Phase | Strategy |
|---|---|
| Miles 1-6 | Start slow, walk aid stations |
| Miles 7-13 | Find rhythm, take fluids |
| Miles 14-20 | Manage the pain |
| Miles 21-26.2 | Dig deep, finish strong |
Target run pace: 30-60 seconds slower than standalone marathon pace.
Nutrition Strategy
Total Requirements
| Nutrient | Amount | Timing |
|---|---|---|
| Carbs | 600-900g total | Spread across race |
| Fluid | 8-15 liters | Continuous intake |
| Sodium | 1000-2000mg/hour | Especially in heat |
By Leg
| Leg | Carbs/Hour | Notes |
|---|---|---|
| Swim | 0 | Nothing during swim |
| Bike | 60-90g | Mix of liquids and solids |
| Run | 40-60g | Mostly gels and sports drink |
Read our Marathon Nutrition Guide.
Ironman vs Other Distances
| Distance | Swim | Bike | Run | Typical Time |
|---|---|---|---|---|
| Sprint | 750m | 20km | 5km | 1:00-2:00 |
| Olympic | 1.5km | 40km | 10km | 2:00-3:30 |
| Half Ironman | 1.9km | 90km | 21.1km | 4:30-7:00 |
| Ironman | 3.8km | 180km | 42.2km | 8:00-17:00 |
Key Training Benchmarks
Before attempting an Ironman:
| Benchmark | Target |
|---|---|
| Swim | 4km continuous |
| Bike | 5-hour ride at race pace |
| Run | 2.5-hour easy run |
| Brick | 4-hour bike + 1.5-hour run |
| Half Ironman | Complete at least one |
The Mental Challenge
Ironman is as much mental as physical:
| Phase | Mental Challenge |
|---|---|
| Swim | Managing anxiety, finding rhythm |
| Early bike | Patience, resisting the urge to race |
| Late bike | Boredom, discomfort setting in |
| Early run | The lowest point mentally |
| Late run | Pain management, will to finish |
| Final miles | Pure determination |
Common Mistakes
1. Inadequate Preparation
Ironman requires 6-12 months of dedicated training. Shortcuts lead to DNFs (did not finish) or injury.
2. Racing the Bike
The bike feels easy early on. Athletes who push too hard on the bike walk the marathon—or don't finish at all.
3. Nutrition Failures
You MUST practice race nutrition. GI issues are the #1 cause of Ironman DNFs.
4. Ignoring Weather
Heat, humidity, wind, and cold all affect Ironman. Have contingency plans.
Common Questions
How hard is an Ironman?
Extremely challenging. Completing an Ironman requires months of training, proper nutrition, mental toughness, and good pacing. About 90% of starters finish, but many suffer significantly.
How long does it take to train for an Ironman?
For most athletes: 9-12 months of structured training with 10-20 hours per week. Athletes with strong endurance backgrounds may need less; complete beginners should plan 18+ months.
What's a good Ironman time?
- Finishing: Under 17 hours is the cutoff
- Solid: 12-14 hours
- Good: 10-12 hours
- Competitive age-group: 9-10 hours
- Elite age-group: Sub-9 hours
Can anyone do an Ironman?
Technically, most healthy adults can complete an Ironman with sufficient training. However, the time commitment (10-20+ hours/week) and physical demands make it unsuitable for many lifestyles. Start with shorter distances to gauge your interest and capacity.