Half Ironman 70.3 Training Plan
A 12-week 70.3 buildup with a strong indoor cycling backbone, since the bike leg makes up more race time than swim and run combined.
The bike leg of a 70.3 typically takes longer than the swim and run combined, so this 12-week plan puts real structure behind your cycling — sweet spot and threshold work to build bike-specific power, layered around your swim and run training — so you arrive at T2 with legs still capable of running a strong half marathon.
This plan is dynamic
Every cycling session in this plan automatically scales its power targets to your FTP, so it adapts as you get fitter — no need to guess your numbers or redo the math yourself. Life happens too: drag any session to a different day on your calendar whenever your routine changes.
Week-by-week breakdown
Base
Weeks 1–3Building aerobic volume across all three disciplines, with Zone 2 cycling as the backbone.
Build
Weeks 4–7Sweet spot cycling intervals and endurance rides to build race-specific bike power.
Race Simulation
Weeks 8–10Threshold efforts and longer endurance rides that simulate race-day bike pacing.
Taper
Weeks 11–12Reduced volume across all three disciplines to arrive at race day fresh.
Frequently asked questions
Why does this plan focus so heavily on cycling?
The bike leg of a 70.3 is roughly half the total race time — dedicated bike-specific training has an outsized impact on your overall finish time.
Do I still need to swim and run separately?
Yes — this plan structures your cycling in depth but assumes you're layering in your own swim and run sessions around it.