Ironman 70.3 Training Plan: A Complete 20-Week Schedule to Finish a Half Ironman

Ironman 70.3 (Half Ironman) consists of a 1.9 km swim, a 90 km bike, and a 21.1 km run, totaling 113 km. It’s a major milestone for many triathletes—long enough to prove your endurance, but without requiring the same life sacrifice as a full Ironman. Below is a 20-week training plan designed for athletes with a baseline fitness level (able to swim 1 km, bike 50 km, and run 10 km).

Training Plan Overview

Prerequisites

• Prior race experience in Sprint or Olympic distance triathlons
• Currently training 5-8 hours per week
• Able to swim continuously for 1,000 meters or more
• Able to bike continuously for 50 km or more
• Able to run continuously for 10 km or more

Weekly Training Volume Distribution

Phase	Weeks	Weekly Training Hours	Focus
Base Phase	Weeks 1-6	7-9 hours	Build aerobic base
Build Phase	Weeks 7-12	9-12 hours	Improve threshold capacity
Peak Phase	Weeks 13-17	12-15 hours	Simulate race distance
Taper Phase	Weeks 18-20	6-8 hours	Recovery and fine-tuning

Time Allocation by Discipline

• Swim: 20% (3 sessions per week)
• Bike: 45% (3-4 sessions per week, including 1 long ride)
• Run: 30% (3-4 sessions per week, including 1 long run)
• Strength Training: 5% (1-2 sessions per week, reduced entering the peak phase)

Detailed Schedule

Weeks 1-6: Base Building Phase

Goal: Build aerobic foundation, establish training habits, strengthen weak areas

Sample Weekly Schedule (Week 4 example):

Day	Morning	Afternoon/Evening
Monday	Rest	Strength training 45 min
Tuesday	Swim 45 min: Technique + intervals	-
Wednesday	Run 45 min: Easy run	-
Thursday	Swim 45 min: Endurance swim	Bike 60 min: Tempo ride
Friday	Swim 40 min: Speed work	Rest or yoga
Saturday	Bike 2 hours: Long ride (Z2)	-
Sunday	Run 60 min: Long run (Z2)	-

Weekly Training Volume:

• Swim: 4,000-5,000m
• Bike: 80-100 km
• Run: 25-30 km
• Total hours: Approximately 8 hours

Weeks 7-12: Intensity Build-Up Phase

Goal: Raise lactate threshold, introduce brick training, increase distance

Sample Weekly Schedule (Week 10 example):

Day	Morning	Afternoon/Evening
Monday	Rest	Strength training 40 min (reduced)
Tuesday	Swim 50 min: Interval set 10×100m	Run 40 min: Tempo run
Wednesday	Bike 75 min: Including 3×10 min FTP intervals	-
Thursday	Swim 50 min: Open water simulation	Run 45 min: Easy run
Friday	Swim 45 min: Continuous endurance swim 1,500m	Rest
Saturday	Brick: Bike 2.5 hours + Run 30 min	-
Sunday	Run 75 min: Long run with pace segments	-

Weekly Training Volume:

• Swim: 5,000-6,500m
• Bike: 100-130 km
• Run: 35-45 km
• Total hours: Approximately 10-11 hours

Weeks 13-17: Peak Phase

Goal: Reach maximum training volume, full-distance simulation, refine race strategy

Sample Weekly Schedule (Week 15 example):

Day	Morning	Afternoon/Evening
Monday	Rest	Core training 30 min
Tuesday	Swim 55 min: Race pace 2×800m	Run 50 min: Intervals 6×1km
Wednesday	Bike 90 min: Sweet Spot intervals	-
Thursday	Swim 50 min: Open water practice	Run 40 min: Recovery run
Friday	Swim 45 min	Rest
Saturday	Long Brick: Bike 3.5 hours + Run 45 min	-
Sunday	Run 90 min: Long run (16-18 km)	-

Weekly Training Volume:

• Swim: 6,000-7,500m
• Bike: 130-160 km
• Run: 45-55 km
• Total hours: Approximately 13-14 hours

Week 16 Focus: Full-distance simulation

• Swim 2,000m + Bike 80-90km + Run 15km
• Execute at 90% of race pace
• Fully test transition流程 and nutrition strategy

Weeks 18-20: Taper Phase

Goal: Allow the body to fully recover and arrive at the start line in peak condition

Week	Training Volume	Focus
Week 18	70% of peak volume	Reduce time, maintain intensity
Week 19	50% of peak volume	Short distance, high quality
Week 20 (Race Week)	30% of peak volume	Easy activity + race

Race Week Sample Schedule:

Day	Training
Monday	Swim 20 minutes (easy)
Tuesday	Bike 30 minutes (including 3×2 minutes at race pace)
Wednesday	Run 20 minutes (including 4×1 minute fast)
Thursday	Swim 15 minutes open water adaptation + course recon
Friday	Complete rest or 15-minute walk
Saturday	Race Day
Sunday	Recovery

Nutrition Strategy

Daily Training Period Nutrition

• Daily Caloric Needs: Basal metabolic rate + training expenditure (approximately 2,500-3,500 kcal)
• Carbohydrates: 6-8 g/kg body weight/day
• Protein: 1.4-1.8 g/kg body weight/day
• Fat: 20-30% of total calories

Race Day Nutrition Plan

Pre-Race Dinner (Night Before the Race):

• High carbohydrate, low fiber, low fat
• Recommended: White rice + chicken breast + a small amount of vegetables
• Timing: 12-14 hours before the race

Pre-Race Breakfast (3 Hours Before the Race):

• 300-500 kcal
• Primarily carbohydrate-based
• Recommended: White toast + peanut butter + banana + sports drink

In-Race Fueling:

Segment	Time	Fueling Content	Intake Per Hour
Swim	35-50 min	No fueling needed	-
T1	2-3 min	One sip of water	-
Bike (First Half)	0-60 min	Sports drink + energy gel	60-70g carbs
Bike (Second Half)	60-120+ min	Sports drink + energy gel + solid food	60-80g carbs
T2	1-2 min	Energy gel + water	-
Run	0-120 min	Cola + energy gel + water	40-60g carbs

Common Foods at Taiwan Aid Stations: Bananas, cherry tomatoes, salt, water, sports drinks, cola (second half of the race)

Gear Upgrade Recommendations (In Order of Priority)

Priority	Gear	Budget	Benefit
1	Triathlon suit (one-piece)	NT$3,000-8,000	One suit covers all three disciplines
2	Aerobars	NT$2,000-5,000	Saves 15-20 minutes on the bike leg
3	Power meter	NT$12,000-25,000	Precise pacing
4	Quick-lace shoelaces	NT$200-400	Saves 30 seconds in transitions
5	Triathlon-specific running shoes	NT$3,000-5,000	Quick to put on and take off
6	Aero helmet	NT$3,000-8,000	Saves 3-5 minutes on the bike leg

Frequently Asked Questions

Q: Should I use a road bike or a triathlon bike?
A: If you only have a road bike, adding aerobars is sufficient. The main advantage of a triathlon bike is aerodynamics, but for a 70.3 distance, a road bike with aerobars is already more than enough. Entry-level triathlon bikes cost around NT$50,000-80,000.

Q: Do long-distance training days need to be as long as the race?
A: No. The longest bike training session is about 3.5 hours (approximately 80-100 km), and the longest run is about 18 km. Full-distance fitness will be realized on race day through adrenaline and supercompensation after tapering.

Q: How do I balance training with work and life?
A: Make good use of morning time (5:30-7:00) for swimming or running, lunch breaks for core training, and weekends for long-distance sessions. You can do two sessions a day twice a week (one in the morning, one in the evening); other days, a single session is enough.

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Completing an Ironman 70.3 is not just a race; it is 20 weeks of self-refinement. Follow this plan, trust the process, and when you hear “You are an Ironman” at the finish line, all the hard work will transform into one of the most profound memories of your life.

Related Reading

• Half Ironman 70.3 Training Plan: 16-Week Complete Race Prep Plan
• IRONMAN 70.3 Half Ironman Training Plan: Periodization Design for 24-Week Race Prep
• 70.3 Half Ironman Finish Guide: Breakthrough Pacing for Middle-Distance Athletes
• Olympic Distance 20-Week Training Plan: Weekly Schedule Design Logic