12-Week Half Ironman Triathlon Training Plan

Once you’ve thrashed out a few Olympic-distance triathlons and decided that it’s time to make the leap to a half Ironman, this training plan from endurance coach Steve Whittle will help you to do just that. 

“If you’re comfortable with the Olympic distance, this 12-week plan will allow you to progress to the half Ironman,” says Whittle. If you haven’t completed an Olympic tri, sign up for that distance first and use Whittle’s Olympic triathlon training plan to guide you.

We've also got some triathlon training tips from tri coaches, below the training plan.

12-Week Half Ironman Triathlon Training Plan

The plan below has been specifically designed to help intermediate-level triathletes prepare for the 1.9km swim, 85km ride and 21.1km run of the Woburn Abbey Half-Iron, presented by tri for life.

The plan keeps things simple and uses duration for each session. This ensures the body gets used to working for sustained periods and you don’t need to worry about covering specific distances. It also makes it easier to schedule all the hours of training in around other commitments.

Week 1

Week 2

Week 3

Week 4

Week 5

Week 6

Week 7

Week 8

Week 9

Week 10

Week 11

Week 12

Triathlon Training Tips

Fuel Your Engine

Aim to eat a meal containing a mix of complex and simple carbohydrates, plus some lean protein and healthy fats, two to three hours before your session. Scrambled eggs on wholemeal toast with some fresh fruit is a good example—it’s light and easy to digest and it’ll provide you with a sustained energy boost.

Improve Your Swimming Technique

If you are more efficient in the water, you’ll save energy for the rest of your half Ironman while still speeding through your swim. “Find a group to train with, or get a few private coaching lessons,” says triathlon coach Ian Rooke, who contributed to our guide on how to train for a triathlon. A dedicated tri coach is a better bet because tri swimming technique uses less kicking than traditional front crawl, conserving energy for the road.

Practice Swimming In A Wetsuit

“While wetsuits are great at providing extra warmth and hydrodynamics, they can feel tight and restricting at first,” says Phil Paterson of coaching company RG Active. “It’s important to work with the buoyancy of the wetsuit. The suit’s buoyancy should make everyone quicker, since you sit higher in the water and your legs don’t sink as much.”

Don’t Just Train Indoors

This goes for all three disciplines in the half Ironman. While smashing out sessions in the gym is convenient and great for your fitness, the best prep for your event will be outdoors.

“You need to learn how to tackle wind and rain, particularly on the bike where you’ll be required to brake and corner,” says Paterson. “Another key area not being used when training indoors are the stabilizing muscles in your hips and core, which are essential for efficient running and pedaling. Not only can weaker stabilizing muscles slow you down through inefficiency, they can also lead to a greater risk of injury.”