Overview

The Half Ironman (70.3) is the bridge between short-course racing and full Ironman distance — 1.9km swim, 90km bike, and a half marathon (21.1km) run. It's a true endurance event that rewards smart training, disciplined nutrition, and mental resilience.

This 16-week plan assumes you've completed at least one Olympic distance triathlon and can comfortably swim 1.5km, ride 60+ km, and run 10km.

Golden Rule: In 70.3 racing, the athlete who slows down the least wins. Pacing and fuelling are everything.

What You'll Need

Swim: Wetsuit (most 70.3 races are open water), goggles, anti-fog spray, swim skin for warmer races
Bike: Road or tri bike in good mechanical order, aero bars (recommended), spare tubes, multi-tool
Run: Tested running shoes, race belt, visor, sunscreen
Nutrition: Gels, bars, electrolyte mix — enough to fuel 5+ hours of racing
Recovery: Foam roller, compression socks, epsom salts

The 16-Week Plan

Phase 1: Base Building (Weeks 1–4)

Build aerobic capacity across all three disciplines. Keep efforts conversational.

Week	Swim	Bike	Run	Brick / Other
1	1.5 km drills + steady	60 min easy	35 min easy	Sat: 50 min bike → 20 min run
2	1.6 km with 6 × 100m fast	70 min with 4 × 3 min efforts	40 min easy	Sat: 60 min bike → 20 min run
3	1.8 km continuous	80 min steady	45 min with 3 × 3 min fast	Sat: 70 min bike → 25 min run
4	1.2 km easy (recovery)	45 min easy spin	30 min easy jog	Rest or yoga

Phase 2: Building Volume (Weeks 5–8)

Increase distance progressively. Introduce race-specific intensities.

Week	Swim	Bike	Run	Brick / Other
5	1.9 km with pace efforts	90 min with 3 × 5 min at race effort	50 min with 4 × 3 min fast	Sat: 75 min bike → 30 min run
6	2 km continuous	100 min steady	55 min easy	Sat: 90 min bike → 30 min run
7	2 km with 8 × 100m race pace	110 min with 2 × 10 min at race effort	55 min with 3 × 5 min fast	Sat: 90 min bike → 35 min run
8	1.5 km easy (recovery)	60 min easy spin	35 min easy jog	Rest or light cross-train

Week 8 is a recovery week. You've built significant volume — let your body consolidate before the peak phase.

Phase 3: Peak Training (Weeks 9–12)

The hardest block. Long rides and brick sessions simulate race conditions.

Week	Swim	Bike	Run	Brick / Other
9	2 km with race-pace intervals	120 min with 3 × 8 min at race effort	60 min with 5 × 3 min fast	Sat: 100 min bike → 35 min run
10	2.2 km continuous	135 min steady at target pace	65 min easy	Sat: 110 min bike → 40 min run
11	2 km with 4 × 200m fast	150 min at race effort	70 min with 3 × 5 min fast	Sat: 120 min bike → 45 min run
12	1.5 km easy (recovery)	70 min easy spin	40 min easy jog	Rest or light stretching

Phase 4: Taper and Race (Weeks 13–16)

Reduce volume while maintaining intensity. Arrive at race day fresh and sharp.

Week	Swim	Bike	Run	Brick / Other
13	1.8 km with race-pace efforts	100 min with 2 × 8 min at race effort	55 min with 4 × 3 min fast	Sat: 80 min bike → 30 min run
14	1.5 km technique + easy	75 min easy	45 min easy	Sat: 50 min bike → 20 min run
15	1.2 km easy with drills	50 min easy spin	30 min easy jog	Sat: 30 min bike → 15 min run
16	800m easy (stay loose)	25 min easy spin	15 min easy jog	RACE DAY! Half Ironman 70.3!

Periodisation Overview

Phase	Weeks	Focus	Volume
Base	1–4	Aerobic fitness, technique, habit	Low–moderate
Build	5–8	Increasing distance, race-specific work	Moderate–high
Peak	9–12	Maximum volume, race simulation	High
Taper	13–16	Reduce volume, maintain sharpness	Decreasing

Race Nutrition Plan

You'll be racing for 4.5–7 hours. Getting nutrition wrong will end your race. Practise this in training.

When	What	How Much
Night before	Carb-rich dinner — pasta, rice, bread	Normal portion, don't overload
Race morning	Porridge, toast + banana, 3 hours before	~500 calories
Swim	Nothing — just focus on swimming	—
Bike (every 20–30 min)	Alternate gels and bars + electrolyte drink	60–80g carbs per hour
Run (every 3–4 km)	Gels + water at aid stations	40–60g carbs per hour
Post-race	Protein + carbs within 30 min	Recovery shake, real food as soon as possible

Test everything in training. Your stomach needs to be trained just like your legs. Never try new nutrition on race day.

Mental Strategies for 70.3

Strategy	How to Use It
Chunk the race	Don't think about 70.3 miles. Think: "Just finish the swim. Now just ride to the halfway turn."
Process goals	Focus on controllables — cadence, breathing, nutrition timing
Mantras	Pick 2–3 short phrases: "Smooth and strong", "I trained for this", "One more aid station"
Visualisation	In the weeks before the race, visualise each leg going well. Picture yourself crossing the finish line
Accept the bad patches	They will come. They will also pass. Keep moving forward

Race Execution Tips

Swim: Start wide to avoid the washing machine. Settle into your rhythm early. Sight every 6–8 strokes
T1: Take 10 seconds to breathe. Rushing leads to mistakes
Bike: Ride at 75–80% effort. Eat and drink on schedule. Save matches for the run
T2: Grab a gel, change shoes, and go. Keep it simple
Run: The first 3 km will feel terrible — your legs are adjusting. Run by feel, not by watch. Walk aid stations if needed
Finish line: Soak it in. You've just completed one of endurance sport's greatest challenges

What's Next?

You've finished a Half Ironman — that's a phenomenal achievement. From here:

Sharpen your swim — work on open water technique with our Intermediate Swimming guide
Build cycling endurance — check out our Intermediate Cycling guide
Chase a faster time — repeat this plan with higher intensity targets
Dream bigger — start researching full Ironman training when the time is right

Half Ironman Training Plan🔒

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