CorrCoach free training plan. corrcoach.com/plans/half-ironman-70-3. General guidance, not medical advice.

By The CorrCoach Team Not reviewed by a doctor or coach Updated October 28, 2026

Half Ironman 70.3 training plan: 16 to 20 weeks

For a first or second middle-distance race. Two swims, two rides and two runs a week, one long ride, one long run, a lighter week every fourth week and a two-week taper. You can start at week 5 if you have 16 weeks and the fitness for it.

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The plan at a glance.

If you have 16 weeks, start at week 5. That works only if you already ride for 105 minutes and run for 60 minutes comfortably, which is where week 3 ends. With fewer than 16 weeks, or with less base, pick a later race. Do not skip weeks. If you have more than 20 weeks, repeat weeks 5 to 8 as an extra base block.

Race: Half Ironman 70.3: 1.9 km swim, 90 km bike, 21.1 km run (70.3 miles in total)
Length: 20 weeks (16 weeks from week 5)
Weekly time: 4 h 35 min to 9 h 40 min a week
Sessions: 6 sessions, Monday off

Who this plan is for.

This is a plan for the athlete who has done a sprint or Olympic race, or has trained steadily for a few months, and now wants a half Ironman without handing over their life to it. It starts at about 5 hours 15 minutes a week and peaks at about 9 hours 40 minutes.

It is a finish-comfortably plan, not a podium plan. Almost everything is easy or steady, with a few short pieces at race effort. That fits the research on endurance training: studies of competitive athletes find roughly 80 percent of sessions at low intensity. For most people with a job, a plan that is mostly easy is the one that gets finished.

Where you need to be before week 1.

You can swim 800 m without stopping, in any stroke.
You can ride for 90 minutes and run for 45 minutes, on separate days, without being wrecked the next day.
You have trained 3 to 5 times a week for the last 8 weeks, or finished a sprint or Olympic race in the last year.
You can fit about 9 to 10 hours into your biggest week, including a long ride of around 3 hours on one day and a long run of about 90 minutes on another.
You have talked to a doctor and are free of the symptoms listed under “Stop and get medical advice” below.

Before you start

Check with a doctor before you start, especially if you have not trained regularly lately, have a heart, lung or joint condition, are pregnant, or have ever had chest pain or fainting when you exercise. A short screening questionnaire such as the PAR-Q+ is a good first step, and a doctor can tell you if you need more than that.

Stop and get medical advice if you notice

Chest pain, pressure or tightness
Dizziness, light-headedness or feeling faint
Breathlessness that is out of proportion to the effort, or a racing or irregular heartbeat
Sharp pain, or any pain that gets worse as you move
Numbness, tingling or sudden weakness

Stop the session when any of these appear. Do not finish the workout, and do not make it up later in the week. If pain is mild but still there the next morning, take the day off, and see a physio or doctor if it lasts more than a few days.

How hard is easy?

Every session has an effort on a 1 to 10 scale (RPE, rate of perceived exertion) and a talk test. No watch, heart rate strap or power meter is needed.

Effort scale used in every session
Effort	Talk test	What it feels like
EasyRPE 2 to 3	You could chat in full sentences and sing a line of a song without gasping.	Like you could keep going for hours. Most of your training is here.
SteadyRPE 4 to 5	You can talk in short sentences. Your breathing is noticeable but never ragged.	Working, but in control. A pace you could hold for a long ride or a race-day swim.
Comfortably hardRPE 6 to 7	Only a few words at a time. You are focused on holding the effort.	Like a pace you could hold for about 30 to 60 minutes, and would not want to hold for 90.
HardRPE 8	One or two words, if that. You are counting down the last few seconds.	You could hold it for 2 to 4 minutes. Used rarely, in short pieces with long rests.

How the weeks fit together.

Build, then rest, then build more. The rest weeks are part of the plan.

Phases of the plan
Phase	Weeks	What it is for
Base	Weeks 1 to 3, 5 to 7	Aerobic base, technique and the first tempo work.
Recovery	Weeks 4, 8, 12 and 16	About a quarter less time, so the work settles in.
Build	Weeks 9 to 11, 13 to 15	Bricks start. Race effort for longer. The long ride grows past 3 hours.
Peak	Weeks 17 and 18	The longest ride and run, plus a race rehearsal.
Taper	Week 19 and the start of week 20	Cut time by about a third, keep a few short race-effort pieces.
Race week	Week 20	Short and easy. Race on Sunday.

Week by week.

Times are totals for the session, in minutes. Do the sessions in order, and take the rest days. If a week goes wrong, read the section on missed weeks before you change anything.

Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
Week 7
Week 8
Week 9
Week 10
Week 11
Week 12
Week 13
Week 14
Week 15
Week 16
Week 17
Week 18
Week 19
Week 20

Week 1Base · 5 h 15 min

Settle into the routine. Easy aerobic work and a lot of technique.

Sessions in week 1
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 6 × 100 m steady with 20 s rest, 200 m easy.A steady rhythm over short repeats.	40 min	Easy warm-up, 100s at RPE 4 to 5
Wed	Ride 60 min easy, with 4 × 1 min of fast pedalling (cadence about 100) and 3 min easy between.Leg speed and smooth pedalling. No strain.	1 h	Easy, RPE 2 to 3
Thu	Run 40 min easy, then 6 × 20 s relaxed strides with 40 s walking.Aerobic base, and some quick running to keep your form sharp.	40 min	Easy, RPE 2 to 3
Fri	Swim technique: 400 m easy, 8 × 50 m drills (catch-up, fingertip drag), 6 × 100 m pull buoy with 15 s rest.The pull buoy cuts the legs out so you can feel your arm stroke.	35 min	Easy, RPE 2 to 3
Sat	Ride 90 min easy on a mostly flat route. Eat and drink every 20 min.Starts the long-ride habit, and practises taking in fuel.	1 h 30 min	Easy, RPE 2 to 3
Sun	Run 50 min easy.Your first long run of the plan. Keep the pace at one where you can talk.	50 min	Easy, RPE 2 to 3

Rest: Mon.

Week 2Base · 5 h 30 min

A little more of the same.

Sessions in week 2
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 5 × 150 m steady with 20 s rest, 200 m easy.A longer repeat, still with rests.	40 min	Easy warm-up, 150s at RPE 4 to 5
Wed	Ride 65 min with 3 × 8 min steady (RPE 5), 4 min easy between.Introduces a steady effort for longer pieces.	1 h 5 min	Easy, with 3 × 8 min at RPE 5
Thu	Run 40 min: 10 min easy, 2 × 8 min at RPE 6 with 3 min jog between, 7 min easy.A first taste of a comfortably hard run.	40 min	Easy, with 2 × 8 min at RPE 6
Fri	Swim technique: 400 m easy, 8 × 50 m breathing every 3, 5, 3, 5 strokes, 6 × 100 m pull with 15 s rest.Breathing on both sides evens out your stroke and helps in choppy water.	35 min	Easy, RPE 2 to 3
Sat	Ride 95 min easy, on a route with a few small hills.Adds a little time and a little terrain.	1 h 35 min	Easy, RPE 2 to 3
Sun	Run 55 min easy.A small step up from last week.	55 min	Easy, RPE 2 to 3

Rest: Mon.

Week 3Base · 6 h

The biggest week of the first block. Next week is lighter.

Sessions in week 3
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 4 × 200 m steady with 25 s rest, 200 m easy.Steady swimming in longer pieces.	45 min	Easy warm-up, 200s at RPE 4 to 5
Wed	Ride 65 min with 3 × 10 min steady (RPE 5), 4 min easy between.More time at the effort you will race at.	1 h 5 min	Easy, with 3 × 10 min at RPE 5
Thu	Run 45 min: 10 min easy, 3 × 8 min at RPE 6 with 3 min jog between, rest easy.Builds your ability to hold a comfortably hard pace.	45 min	Easy, with 3 × 8 min at RPE 6
Fri	Swim technique: 400 m easy, 6 × 50 m drills, 4 × 150 m pull with 20 s rest.Keeps technique work in the week.	40 min	Easy, RPE 2 to 3
Sat	Ride 105 min easy. Take on fuel every 20 min and finish with 10 min spinning an easy gear.Time in the saddle. The bike is nearly half of race day.	1 h 45 min	Easy, RPE 2 to 3
Sun	Run 60 min easy.An hour on your feet, at a pace you could keep for much longer.	1 h	Easy, RPE 2 to 3

Rest: Mon.

Week 4Recovery week · 4 h 35 min

A lighter week, about a quarter less. The first block of work is absorbed here.

Sessions in week 4
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 4 × 100 m easy with 20 s rest, 200 m easy.Relaxed swimming.	35 min	Easy, RPE 2 to 3
Wed	Ride 50 min easy.Loosens the legs.	50 min	Easy, RPE 2 to 3
Thu	Run 35 min easy.Short and comfortable.	35 min	Easy, RPE 2 to 3
Fri	Swim technique: 300 m easy, 6 × 50 m drills, 4 × 100 m pull.A calm technique session.	30 min	Easy, RPE 2 to 3
Sat	Ride 80 min easy.Still a long ride, but with room to enjoy it.	1 h 20 min	Easy, RPE 2 to 3
Sun	Run 45 min easy.Keeps the habit.	45 min	Easy, RPE 2 to 3

Rest: Mon.

Week 5Base · 6 h 10 min

Back to full work, a notch above week 3.

Sessions in week 5
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 3 × 300 m steady with 30 s rest, 200 m easy.Longer steady pieces.	45 min	Easy warm-up, 300s at RPE 4 to 5
Wed	Ride 70 min with 3 × 12 min steady (RPE 5 to 6), 4 min easy between.Longer pieces at the effort you will race at.	1 h 10 min	Easy, with 3 × 12 min at RPE 5 to 6
Thu	Run 45 min: 15 min easy, 6 × 45 s uphill at RPE 7 (jog back down), 10 min easy.Hill reps build leg strength with less impact than fast running on the flat.	45 min	Easy, with 6 × 45 s at RPE 7
Fri	Swim technique: 400 m easy, 8 × 50 m drills, 6 × 100 m with 15 s rest and a focus on a long stroke.Fewer strokes per length means less work for the same speed.	40 min	Easy, RPE 2 to 3
Sat	Ride 110 min easy on a rolling route. Drink every 15 to 20 min and eat something at 45 and 90 min.Practises the fuelling plan you will use in the race.	1 h 50 min	Easy, RPE 2 to 3
Sun	Run 60 min easy.Holds your long-run volume.	1 h	Easy, RPE 2 to 3

Rest: Mon.

Week 6Base · 6 h 35 min

Longer rides, longer swims.

Sessions in week 6
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 4 × 300 m steady with 30 s rest, 200 m easy.About 1,800 m. Close to race distance in total.	50 min	Easy warm-up, 300s at RPE 4 to 5
Wed	Ride 70 min with 3 × 15 min at RPE 5 to 6, 4 min easy between.The longest steady pieces so far.	1 h 10 min	Easy, with 3 × 15 min at RPE 5 to 6
Thu	Run 50 min: 10 min easy, 2 × 12 min at RPE 6 with 4 min jog between, 8 min easy.A longer comfortably hard effort.	50 min	Easy, with 2 × 12 min at RPE 6
Fri	Swim technique: 400 m easy, 6 × 50 m drills, 4 × 200 m pull with 20 s rest.Easy volume that builds feel for the water.	40 min	Easy, RPE 2 to 3
Sat	Ride 120 min easy, with hills if you can find them. Take in fuel every 20 min.Two hours in the saddle for the first time.	2 h	Easy, RPE 2 to 3
Sun	Run 65 min easy.A small step up.	1 h 5 min	Easy, RPE 2 to 3

Rest: Mon.

Week 7Base · 7 h 5 min

The last big week of the base block. Next week is lighter.

Sessions in week 7
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, one continuous 1,000 m steady, 200 m easy.Your first long unbroken swim. Settle in and breathe.	50 min	Easy warm-up, 1,000 m at RPE 4 to 5
Wed	Ride 75 min with 2 × 20 min at RPE 6, 5 min easy between.Comfortably hard work on the bike, kept to two pieces.	1 h 15 min	Easy, with 2 × 20 min at RPE 6
Thu	Run 55 min: 10 min easy, 20 min at RPE 6, rest easy.A continuous tempo, as close as this plan gets to a 10 km effort.	55 min	Easy, 20 min at RPE 6
Fri	Swim technique: 400 m easy, 8 × 50 m drills, 6 × 100 m pull with 15 s rest, 200 m easy.More technique.	45 min	Easy, RPE 2 to 3
Sat	Ride 130 min easy. Practise drinking and eating while riding at a steady pace.A bigger ride. Do not push the pace in the first hour.	2 h 10 min	Easy, RPE 2 to 3
Sun	Run 70 min easy.Longest run of the base block.	1 h 10 min	Easy, RPE 2 to 3

Rest: Mon.

Week 8Recovery week · 5 h 10 min

A lighter week. Sleep, eat well and let the work settle.

Sessions in week 8
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 5 × 100 m easy, 200 m easy.Relaxed time in the water.	40 min	Easy, RPE 2 to 3
Wed	Ride 55 min easy, with 3 × 1 min spin-ups.Loosens the legs.	55 min	Easy, RPE 2 to 3
Thu	Run 40 min easy.Short and comfortable.	40 min	Easy, RPE 2 to 3
Fri	Swim technique: 300 m easy, 6 × 50 m drills, 4 × 100 m pull.A calm technique session.	35 min	Easy, RPE 2 to 3
Sat	Ride 90 min easy.A long ride with lighter legs.	1 h 30 min	Easy, RPE 2 to 3
Sun	Run 50 min easy.Keeps the habit.	50 min	Easy, RPE 2 to 3

Rest: Mon.

Week 9Build · 7 h 20 min

Bricks start. After Saturday’s ride, run for 10 minutes without stopping.

Sessions in week 9
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 6 × 200 m at RPE 5 with 20 s rest, 200 m easy.Steady swimming in medium pieces.	50 min	Easy warm-up, 200s at RPE 5
Wed	Ride 80 min with 3 × 15 min at RPE 6, 5 min easy between.Builds your steady power for the long ride.	1 h 20 min	Easy, with 3 × 15 min at RPE 6
Thu	Run 55 min: 15 min easy, 8 × 45 s uphill at RPE 7, jog down, rest easy.Hill strength.	55 min	Easy, with 8 × 45 s at RPE 7
Fri	Swim technique: 400 m easy, 6 × 50 m drills, 4 × 100 m practice start and sighting every 8 strokes.Practises sighting, the skill that keeps you on course.	45 min	Easy, RPE 2 to 3
Sat	Brick: ride 125 min easy to steady, then run 10 min straight after at easy effort.Your first brick. Expect heavy legs for the first 3 to 5 minutes.	2 h 15 min	Easy to steady, RPE 3 to 4
Sun	Run 75 min easy.A long run on tired legs from yesterday.	1 h 15 min	Easy, RPE 2 to 3

Rest: Mon.

Week 10Build · 7 h 40 min

More time at race effort.

Sessions in week 10
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 2 × 800 m steady with 60 s rest, 200 m easy.About 2,200 m. More than the race swim, in two pieces.	55 min	Easy warm-up, 800s at RPE 5
Wed	Ride 80 min with 2 × 25 min at RPE 6, 5 min easy between.Longer pieces at your upper steady effort.	1 h 20 min	Easy, with 2 × 25 min at RPE 6
Thu	Run 60 min: 10 min easy, 25 min at RPE 6, rest easy.A longer tempo.	1 h	Easy, 25 min at RPE 6
Fri	Swim technique: 400 m easy, 8 × 50 m drills, 6 × 100 m pull with 15 s rest.Keeps technique work in the week.	45 min	Easy, RPE 2 to 3
Sat	Brick: ride 130 min easy to steady, then run 15 min easy.The same brick, five minutes longer.	2 h 25 min	Easy to steady, RPE 3 to 4
Sun	Run 75 min easy.Holds the long-run volume.	1 h 15 min	Easy, RPE 2 to 3

Rest: Mon.

Week 11Build · 8 h 5 min

The biggest week of the build block, with one set of harder intervals.

Sessions in week 11
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 10 × 100 m at RPE 6 with 15 s rest, 400 m easy pull.Quicker repeats to make race pace feel easier.	55 min	Easy warm-up, 100s at RPE 6
Wed	Ride 85 min with 4 × 12 min at RPE 6, 4 min easy between.Broken into shorter pieces so you can hold the effort.	1 h 25 min	Easy, with 4 × 12 min at RPE 6
Thu	Run 60 min: 15 min easy, 3 × 10 min at RPE 6 with 3 min jog between, rest easy.Tempo volume, with the harder bits broken up.	1 h	Easy, with 3 × 10 min at RPE 6
Fri	Swim technique: 400 m easy, 8 × 50 m drills, 4 × 200 m pull with 20 s rest.More technique.	50 min	Easy, RPE 2 to 3
Sat	Brick: ride 140 min, with the middle hour at RPE 4 to 5, then run 15 min easy.A longer ride with a steadier middle.	2 h 35 min	Easy, with the middle hour at RPE 4 to 5
Sun	Run 80 min easy.Long run at a conversational pace.	1 h 20 min	Easy, RPE 2 to 3

Rest: Mon.

Week 12Recovery week · 5 h 55 min

A lighter week. About a quarter less.

Sessions in week 12
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 6 × 100 m easy, 200 m easy.Relaxed time in the water.	45 min	Easy, RPE 2 to 3
Wed	Ride 65 min with 3 × 8 min at RPE 5, 4 min easy between.Keeps some steady work in a light week.	1 h 5 min	Easy, with 3 × 8 min at RPE 5
Thu	Run 45 min easy.Short and comfortable.	45 min	Easy, RPE 2 to 3
Fri	Swim technique: 300 m easy, 6 × 50 m drills, 4 × 100 m pull.A calm technique session.	35 min	Easy, RPE 2 to 3
Sat	Brick: ride 100 min easy, then run 10 min easy.A shorter long ride with a short brick.	1 h 50 min	Easy, RPE 2 to 3
Sun	Run 55 min easy.Keeps the habit.	55 min	Easy, RPE 2 to 3

Rest: Mon.

Week 13Build · 8 h 20 min

Back to full work. The long ride gets close to three hours.

Sessions in week 13
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 1,500 m continuous steady, 200 m easy.Close to race distance in one go.	55 min	Easy warm-up, 1,500 m at RPE 5
Wed	Ride 85 min with 2 × 30 min at RPE 5 to 6 (your race effort), 5 min easy between.Race-effort riding in long pieces.	1 h 25 min	Easy, with 2 × 30 min at RPE 5 to 6
Thu	Run 65 min: 10 min easy, 30 min at RPE 6, rest easy.A longer continuous tempo.	1 h 5 min	Easy, 30 min at RPE 6
Fri	Swim technique and open-water skills: 400 m easy, 6 × 50 m drills, 6 × 100 m with sighting every 6 strokes.If you can swim in open water, do this session there with a friend or at a supervised swim.	50 min	Easy, RPE 2 to 3
Sat	Brick: ride 150 min with the last hour at RPE 4 to 5, then run 15 min at RPE 4 to 5.Practises running on tired legs at a steady effort.	2 h 45 min	Easy to steady, RPE 3 to 5
Sun	Run 80 min easy.Holds the long-run volume.	1 h 20 min	Easy, RPE 2 to 3

Rest: Mon.

Week 14Build · 8 h 50 min

Close to the biggest rides. Fuel and drink as you will in the race.

Sessions in week 14
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 3 × 600 m steady with 45 s rest, 200 m easy.About 2,400 m, with the middle at RPE 5.	1 h	Easy warm-up, 600s at RPE 5
Wed	Ride 90 min with 3 × 20 min at RPE 5 to 6, 5 min easy between.Race effort in shorter pieces.	1 h 30 min	Easy, with 3 × 20 min at RPE 5 to 6
Thu	Run 65 min: 10 min easy, 3 × 12 min at RPE 6 with 3 min jog between, rest easy.Tempo in pieces.	1 h 5 min	Easy, with 3 × 12 min at RPE 6
Fri	Swim technique: 400 m easy, 8 × 50 m drills, 4 × 200 m pull with 20 s rest.Easy technique work.	50 min	Easy, RPE 2 to 3
Sat	Brick: ride 165 min with the middle 90 min at RPE 4 to 5, then run 15 min at easy to steady effort.Dress rehearsal for the fuelling plan.	3 h	Easy to steady, RPE 3 to 5
Sun	Run 85 min easy.A long run at a pace you could keep for longer.	1 h 25 min	Easy, RPE 2 to 3

Rest: Mon.

Week 15Build · 9 h 20 min

The biggest week of the build block. The next one is lighter.

Sessions in week 15
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 1,900 m continuous steady (the race distance), 200 m easy.You swim the full race distance. The time is not important. The calm is.	1 h	Easy warm-up, 1,900 m at RPE 5
Wed	Ride 90 min with 2 × 30 min at RPE 5 to 6, 5 min easy between.Race effort for longer.	1 h 30 min	Easy, with 2 × 30 min at RPE 5 to 6
Thu	Run 70 min: 10 min easy, 35 min at RPE 6, rest easy.The longest tempo.	1 h 10 min	Easy, 35 min at RPE 6
Fri	Swim technique: 400 m easy, 8 × 50 m drills, 6 × 100 m pull with 15 s rest, 200 m easy.Easy technique work.	55 min	Easy, RPE 2 to 3
Sat	Brick: ride 175 min (the long ride), with 2 × 40 min at RPE 4 to 5 and the rest easy, then run 20 min at RPE 4 to 5.Your longest day of the plan, and a good check of your fuelling.	3 h 15 min	Easy to steady, RPE 3 to 5
Sun	Run 90 min easy. Walk through any aid stations.The longest run of the plan, kept easy.	1 h 30 min	Easy, RPE 2 to 3

Rest: Mon.

Week 16Recovery week · 6 h 40 min

A lighter week. This is the one that makes the final block work.

Sessions in week 16
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 6 × 100 m easy, 400 m pull.Relaxed swimming.	50 min	Easy, RPE 2 to 3
Wed	Ride 70 min with 3 × 10 min at RPE 5, 5 min easy between.Keeps some steady work in a light week.	1 h 10 min	Easy, with 3 × 10 min at RPE 5
Thu	Run 50 min easy.Short and comfortable.	50 min	Easy, RPE 2 to 3
Fri	Swim technique: 300 m easy, 6 × 50 m drills, 4 × 100 m pull.A calm technique session.	40 min	Easy, RPE 2 to 3
Sat	Brick: ride 115 min easy, then run 15 min easy.A shorter ride, still with a brick.	2 h 10 min	Easy, RPE 2 to 3
Sun	Run 60 min easy.Keeps the habit.	1 h	Easy, RPE 2 to 3

Rest: Mon.

Week 17Peak · 9 h 40 min

The longest week. Race effort in careful doses.

Sessions in week 17
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 2 × 1,000 m steady with 60 s rest, 200 m easy.More than race distance, in two pieces.	1 h	Easy warm-up, 1,000s at RPE 5
Wed	Ride 90 min with 2 × 30 min at RPE 5 to 6, finishing with 10 min at RPE 6.Practise holding your race effort and finishing a little stronger.	1 h 30 min	Easy, with 2 × 30 min at RPE 5 to 6
Thu	Run 70 min: 10 min easy, 2 × 20 min at RPE 6 with 5 min jog between, rest easy.A strong run, with a short break between the pieces.	1 h 10 min	Easy, with 2 × 20 min at RPE 6
Fri	Swim technique and open-water skills: 400 m easy, 6 × 50 m drills, 6 × 100 m with sighting every 6 strokes.Keeps the stroke long and the head up when you need it.	55 min	Easy, RPE 2 to 3
Sat	Brick: ride 185 min with 2 × 45 min at RPE 5 (race effort) and the rest easy, then run 25 min at RPE 5.The closest the plan comes to the second half of race day.	3 h 30 min	Easy to steady, RPE 3 to 5
Sun	Run 95 min easy. Walk through any aid stations.The last long run before the taper.	1 h 35 min	Easy, RPE 2 to 3

Rest: Mon.

Week 18Peak · 9 h 30 min

A race rehearsal on Saturday. Keep everything else easy.

Sessions in week 18
Day	Session and why	Time	Effort
Tue	Swim: 400 m warm-up, 1,900 m continuous steady with sighting every 8 strokes, 200 m easy. Do this in open water if you can.The full race swim, with the sighting you will use on the day.	1 h	Easy warm-up, 1,900 m at RPE 5
Wed	Ride 90 min with 3 × 20 min at RPE 5 to 6, 5 min easy between.Steady work, no more than race effort.	1 h 30 min	Easy, with 3 × 20 min at RPE 5 to 6
Thu	Run 70 min: 10 min easy, 3 × 10 min at RPE 5 to 6 with 4 min jog between, rest easy.Practice at half-marathon effort.	1 h 10 min	Easy, with 3 × 10 min at RPE 5 to 6
Fri	Swim: 400 m easy, 6 × 50 m drills, 4 × 100 m easy.Keeps technique in the week without cost.	50 min	Easy, RPE 2 to 3
Sat	Race rehearsal: ride 185 min with 90 minutes at RPE 5 (race effort) and your race food and drink, then run 30 min at RPE 5.Use the gear and food you plan to race in. Find out what does not work.	3 h 35 min	Easy to steady, RPE 3 to 5
Sun	Run 85 min easy, or 60 min if your legs are heavy.Easy volume after a big day.	1 h 25 min	Easy, RPE 2 to 3

Rest: Mon.

Week 19Taper · 6 h 15 min

Taper. About a third less, with the same routine and a few short bits at race effort.

Sessions in week 19
Day	Session and why	Time	Effort
Tue	Swim: 300 m warm-up, 1,000 m steady, 200 m easy.Keeps the feel for the water.	45 min	Easy warm-up, 1,000 m at RPE 5
Wed	Ride 60 min with 3 × 8 min at RPE 6, 4 min easy between.Short, sharp reminders of race effort.	1 h	Easy, with 3 × 8 min at RPE 6
Thu	Run 50 min: 15 min easy, 20 min at RPE 6, rest easy.A run at race effort for a shorter time.	50 min	Easy, 20 min at RPE 6
Fri	Swim technique: 300 m easy, 6 × 50 m drills, 6 × 100 m pull.Easy technique.	40 min	Easy, RPE 2 to 3
Sat	Brick: ride 100 min easy to steady, then run 20 min easy.A last, shorter brick.	2 h	Easy to steady, RPE 3 to 4
Sun	Run 60 min easy.Keeps the habit.	1 h	Easy, RPE 2 to 3

Rest: Mon.

Week 20Race week · 2 h 20 min plus the race on Sun

Race week. Short, easy sessions, and everything packed early. The race is on Sunday.

Sessions in week 20
Day	Session and why	Time	Effort
Tue	Swim: 300 m easy, 4 × 100 m steady with 20 s rest. Practise sighting.Loose and relaxed.	25 min	Easy, RPE 2 to 3
Wed	Ride 45 min easy, with 3 × 3 min at race effort (RPE 5 to 6), 3 min easy between.Wakes up the legs without costing you anything.	45 min	Easy, with 3 × 3 min at RPE 5 to 6
Thu	Run 25 min easy, then 4 × 20 s strides.Loose and light.	25 min	Easy, RPE 2 to 3
Fri	Swim 15 min easy, or a short open-water swim if the venue opens for practice.A last feel for the water.	15 min	Easy, RPE 2 to 3
Sat	Shakeout: ride 20 min easy and jog 10 min. Rack your bike and check your gear.A last check that everything works, while there is still time to fix it.	30 min	Easy, RPE 2 to 3

Rest: Mon. Race day: Sun.

Bricks and changeovers.

A brick is a ride followed straight by a run. In a half Ironman, you run 21.1 km on legs that have just ridden 90 km, so you need practice with the feeling.

Bricks start in week 9 with 10 minutes of easy running and grow to 30 minutes in week 18. The long ride before them stays easy to steady. The aim is not to run fast off the bike. It is to learn how your legs feel in the first 5 minutes, and to settle into an easy run. USA Triathlon’s sample brick for 70.3 and full-distance athletes ends with a 40-minute run at zones 1 to 3, mostly easy to steady, which is the shape of the longest bricks here.

Practise the changeover.

Practise the changeover at home: helmet off, bike racked, shoes changed, out the door. In a half Ironman you will take a minute or two.
In the last 10 minutes of every long ride, spin an easier gear at a higher cadence. Your legs will be warm and quick when you start to run.
For the first 5 minutes of every brick run, shorten your stride and go slower than feels natural. Most people find their rhythm after about 10 minutes.
Practise your race food and drink on every ride over two hours. The long-ride rehearsal in week 18 uses exactly what you will use on race day.

Recovery weeks and the taper.

Weeks 4, 8, 12 and 16 are about a quarter lighter than the weeks before. That is deliberate. The best long-term gain comes from alternating load and rest. The joint consensus statement from the European College of Sport Science and the American College of Sports Medicine describes overtraining as the result of an imbalance between training load and recovery.

The plan adds time by about 10 percent a week at most, the same cap CorrCoach’s own planner uses by default. In most weeks it adds less. If a week leaves you unable to do the next one, repeat it instead of moving on.

The taper is week 19 and the first part of week 20. A 2007 meta-analysis of 27 studies found the best tapers lasted about two weeks, cut training volume by roughly 40 to 60 percent, and left intensity and frequency unchanged. This plan cuts about 35 percent in week 19 and more in week 20, and keeps a few short bits at race effort so the legs do not go flat.

If you miss a week or get sick.

Life will get in the way at some point. The rule is simple: you never make up missed sessions, you pick up where your body is.

What to do after missed training
What happened	What to do
You miss 1 to 3 days	Skip them and carry on on the day you are back. If the missed session was the long ride, do not do it on a rest day. The week stays as it is.
You miss a whole week, and you are healthy	Repeat the last week you finished. If that was a recovery week, repeat the one before it.
You miss 2 weeks	Go back two weeks in the plan and rebuild from there. If you are in the peak or taper, do not go back: shorten the taper and keep the race effort easy.
You miss 3 weeks or more	Go back to the last base week you completed, or pick a later race.
You are sick, with fever, chest symptoms or body aches	No training. Follow the illness steps below, and restart at about 70 percent of the planned time. In the final three weeks, do not try to make up the long sessions.

When you are ill.

Fever, chest symptoms, body aches or heavy tiredness mean no training. Rest, drink plenty of fluids and sleep more.
Wait until you have been without a fever for a full day, then start again with easy sessions at about 70 percent of the planned time. Skip the hard parts for the first few days.
See a doctor if you feel worse, if symptoms last more than a few days, or if you had chest pain, breathlessness or a racing heart while ill. Do not restart until you are cleared.
Missed sessions are gone. Never add them to later weeks to catch up.

Race week.

Race week is mostly logistics, and this race is long enough that mistakes with kit and food can cost you hours. Sessions are short and easy.

Monday: check your bike and kit. Replace tyres and brake pads now if they are worn, not on Saturday.
Tuesday to Thursday: do the short sessions in the table. Do not add anything.
Friday: rest. Check the race briefing, the course map, the cut-off times and where you rack the bike. Pack two bags if the race has separate transition bags.
Saturday: do the shakeout, rack your bike and drop your bags. Eat the same foods you used before long sessions, and go to bed on time even if you cannot sleep.
Race morning: eat what you always eat, keep warm before the swim, and swim the first 200 m easy.
On the bike, ride the first hour at RPE 4 to 5, steady after that and ease off in the last 15 minutes. Drink and eat on a schedule, not when you are hungry.
Run the first 3 km slower than you want to. Walk through aid stations, and expect to feel bad at some point around the halfway mark. It usually passes.
If you feel dizzy, get chest pain or notice any other stop sign, stop and get help. No finish is worth it.

Let CorrCoach adapt this plan to you

Twenty weeks is a long time for life to stay the same. CorrCoach Tri builds the weeks from your race date and the hours you really have, then moves sessions when a week goes sideways. Plans are free to start.

Let CorrCoach adapt this plan to you

Sources you can check.

Seiler, What is best practice for training intensity and duration distribution in endurance athletes? (Int J Sports Physiol Perform, 2010)About 80 percent of sessions at low intensity in competitive endurance athletes.
Bosquet and colleagues, Effects of tapering on performance: a meta-analysis (Med Sci Sports Exerc, 2007)A two-week taper with volume cut by 41 to 60 percent and intensity held.
Meeusen and colleagues, Prevention, diagnosis and treatment of the overtraining syndrome (ECSS and ACSM consensus, Med Sci Sports Exerc, 2013)Why load needs to alternate with recovery.
USA Triathlon: How to use brick workouts in triathlon trainingBrick structure for sprint through long-distance races.

Written by The CorrCoach Team. Not reviewed by a doctor or coach. These are general guidelines, so talk to a doctor before you start. They are built from the published sources listed on each page and the conservative build-up rules CorrCoach’s own planner uses.

Questions.

Can I do a half Ironman on 6 hours a week?

You can finish one, but not on this exact plan. The first six weeks fit in 5 to 6.5 hours. Past that, the long ride and long run have to stay long. If your week tops out at 6 hours, give yourself the full 20 weeks, keep the weekend sessions and drop the Friday swim and the Wednesday ride. Plan to finish.

Why is the long run capped at 95 minutes?

Because the race is run on legs that have already ridden 90 km, so you get more from practising a brick than from a longer run. Most 70.3 plans stop the long run at about 90 to 100 minutes for that reason. The rest of the preparation comes from the bricks and the base you built.

I have never swum 1.9 km. Is that a problem?

Not if you follow the swim sessions. You will swim 1,000 m unbroken in week 7, 1,500 m in week 13 and the full distance in weeks 15 and 18. Practise in open water with someone if the race swim is open water.