› Ironman

Training For An Ironman

A 21 Week Plan

Training for an Ironman doesn’t have to be as daunting as it can seem. Everyone can complete an Ironman. This Ironman training plan is designed to help you enjoy the experience!

It is aimed at:

  • Individuals who are active but not in regular Ironman training
  • Individuals who have undertaken a shorter triathlon such as a sprint or Olympic, and who want to make it safely and enjoyably around an Ironman.

If you want to race it and beat times then read our Ironman Training Plan for Racing (coming soon).

As a rough guide anyone wanting to go faster than about 11-11.5 hours should undertake this more advanced programme.

I know I said everyone can complete an Ironman, but don’t mistake that for meaning it is easy!

Finishing one is 50% mental, 30% nutritional and only 20% training. Our Ironman Training Plan is designed to reflect this requirement, so many sessions are intended to challenge you mentally and get you to practice your nutrition strategy.

Even a Pro who is not ready for the challenge and has poor nutrition is unlikely to be able to finish one, unlike all the other distances in triathlon. This is the challenge and the attraction for so many people.


Your first challenge when training for an Ironman is to ensure you know what is going to be required, and then that you still want to do it.

Some questions to ask yourself:

  • Are you ready and able to commit 10 – 18 hours a week for training?
  • Are you prepared to get up early, get a session in before work, go to work and then get another session in? Do you have this much time?
  • Are you prepared to do this when you feel tired, and when you would much rather stay tucked up in bed?

If you are up for the challenge of training for an Ironman, then keep reading. If the thought of this commitment puts you off, revise your personal challenge!


This Ironman training plan assumes that you have a limited training history. Therefore it will start off steadily, but in order get all the work in, the workload will increase fairly rapidly.

We are also assuming that you can actually swim a bit, ride a bike safely and are not injured at all at the beginning of the programme and that you don’t have any medical conditions that would hamper your training or be negatively affected by training.

Aims of the Ironman Training Plan

  • Gradually increase endurance in each discipline
  • Prepare you to complete 12 – 18hrs of continuous exercise and ENJOY IT
  • Practice nutrition strategies
  • Minimise your risk of injury

If you progress quickly and decide to be more aggressive you will be able to move in into our Ironman Training to Race plan (coming soon).

Whilst following this Ironman training plan, please refer to our swim, bike and run training pages for examples and descriptions of types of sessions.

For a description of the different training intensities, our run page and cycling page will help.

Also, you can use our triathlon training planner to input your sessions and record your progress.

You can also download an Excel version of this Ironman training plan here.

Ironman Training Plan

Below is an overview of the 21 week Ironman Training Plan.

As your aim is to get round and enjoy the event, the majority of the training is about helping you to get the endurance to be able to do this. There are not many short cuts to doing this (whatever other sites/coaches might say). You cannot trick yourself over these kinds of durations.

The key when training for an Ironman is being able to train regularly, as well as rest well when planned, and keep the training intensity down. If you train at high intensities, the time required to recover adequately will compromise the volume of training you need to do to successfully complete an Ironman.

So keep the intensity down!

Everyone likes a little burn up with friends or to push themselves on the hills, but be aware that too much of this will create un-recoverable fatigue and will hamper subsequent sessions and therefore limit your training consistency.

Routine is important to most people, and therefore we provide an idea of what the schedule might look like. However it is not set in stone because you may need to re-work some of it to fit your schedule. As the phases change there might be different sessions but we try to keep the type (i.e. swim, bike etc) on the same days to help with this routine.

We have included two races in the schedule. The times where they are scheduled is the ideal scenario, however you might need to move them slightly to fit your schedule and the race calendar.

Ideally the first race would be an Olympic, and would come at the very beginning of the Prep 1 phase. So you have rested, raced and then got back into your training routine.

The second race comes at the end of Prep 2 and could be a half-Ironman.

We do not normally recommend any running races or cycling events as they are too different to what you will encounter in an Ironman and will inevitably add too much intensity.

However open water swim races are a great way of getting used to being around lots of other swimmers and being in the open water.

Initially the programme focuses upon swim and bike, as being better trained in these will mean less fatigue when starting the run.

Adaptation Phases – Rest Weeks

In these planned weeks off you need to keep a little active but allow yourself to recover.

Everyone is different, and some will take most of the week off completely, others will find that just doing about 25% of what you had been doing will help you to maintain the rhythm of training but allow you to recover.

It is very individual so you need to find the right balance for your training and life. The most important thing is that you recover in this week.

You must start the next block ready to go.

Base/Foundation 1 Phase of Training For An Ironman

  • 3 weeks of introduction to training.
  • These first 3 weeks should be performed at a nice easy pace, otherwise you will struggle to complete it all. This is just getting your body conditioned to training on a regular basis and on some days doing a double session.

Base 2 Phase of Training For An Ironman

  • 3 weeks of developing training
  • This block has taken the first one and added a little more volume, and on the swim a little more intensity with the CSS sessions. You should be beginning to feel comfortable with regular training and your speed of recovery will be improving.

Build 1 Phase Of Training For An Ironman

  • 3 weeks of developing training, by introducing some intensity.
  • Many people worry that they have not completed the race distance this far into the programme in one session. However it is not necessary yet. You should accumulate hours of training over a sustained period. Once you have done this you will only need a few really long sessions to get a feel for the race distance, but you need to be ready first.

Build 2 Phase of Training For An Ironman

  • Introduction of more running volume.
  • Some big weeks of training here, and it is the accumulation of the training over each day and week that really counts. However the next block is going to rapidly increase the volume, as you should now be ready for some long sessions.
  • You may be feeling ready to include some unstructured speed work on the bike. You should try to practice how you will be racing, so if you have aerobars on, make sure you use them and pick the pace up, but not too much.
  • Remember the difference between Extensive Endurance and Easy. EE is a good solid endurance pace, whereas Easy is very comfortable. Most will likely race their Ironman event at a mix of Easy and Extensive Endurance pace.

Prep 1 Phase of Ironman Training Plan

  • Race specific durations.
  • In this last 4 weeks of training for an Ironman, we have rapidly increased the volume of some of the sessions. If you have gone well in the previous phases, then this should be a daunting but doable step up. You need to listen to your body and adjust the volumes to challenge yourself, but don’t kill yourself on every session.

Race Week

  • Treat this the same as a rest week, ensuring you are fresh and ready to go on race day.
  • Prepare your gear etc for race day.
  • Read our race day page and follow the advice about race preparation.
  • Go out and enjoy becoming an Ironman!

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