How many weeks to prepare for Half Ironman?

For an athlete at intermediate level, Endu builds a 21-week preparation. If your race is closer, the plan compresses phases while keeping the taper; if it's further away, it extends the base phase.

How many sessions per week?

This example has 4.9 sessions per week. You choose 5 to 7 training days and the exact days (e.g. Tue, Thu, Sat, Sun): the plan sticks to them.

Can I follow sessions on my watch?

Yes: every session exports as .fit, the format read by Garmin, Coros, Suunto, Polar and Wahoo. Import it in your watch app and the guided workout appears on your wrist.

How much does it cost?

14-day free trial, then €7.99/month with no commitment or €59.88/year (€4.99/month). Unlimited objectives and sports.

Half Ironman plan, 5 sessions a week

113 km · swim 1.9 · bike 90 · run 21.1

You have 5 slots a week. Here is how Endu spreads a Half Ironman preparation over 5 sessions: the long run is protected, the quality session comes next, easy runs fill what is left.

Create my plan for Half Ironman

weeks: 21
sessions: 103
sessions / week: 4.9
peak week: 8.3 h

Plan structure

Periodised in phases: build the base, move to race-specific work, then taper before the race.

General preparation
Weeks 1–2 · 2 wk
Base
Weeks 3–8 · 6 wk
Build
Weeks 9–13 · 5 wk
Specific
Weeks 14–18 · 5 wk
Taper
Weeks 19–20 · 2 wk
Race week
Weeks 21–21 · 1 wk

Volume progression

Week by week: lighter recovery weeks are built in to absorb the load.

Wk	Phase	Hours	km
1	General preparation	4.6 h	21
2	General preparation	4.8 h	22
3	Base	6.6 h	25
4	Baserecovery	5.6 h	22
5	Base	6.7 h	26
6	Base	6.8 h	26
7	Base	6.9 h	27
8	Baserecovery	6 h	23
9	Build	6.7 h	28
10	Build	6.9 h	29
11	Build	7 h	29
12	Buildrecovery	6.1 h	26
13	Build	7.1 h	30
14	Specific	7.9 h	25
15	Specific	8.1 h	26
16	Specificrecovery	6.4 h	20
17	Specific	8.2 h	26
18	Specific	8.3 h	27
19	Taper	5.1 h	27
20	Taper	4.1 h	23
21	Race week	2 h	8

Sample week — week 13 (Build)

Real sessions from the plan with their targets. Each session is detailed step by step and exportable as .fit.

MondayEasy
🚴 Bike endurance 139min
2 h 19
TuesdayVery hard
Intervals 5×1.2km
1 h 03 · 12.1 km
ThursdayHard
🏊 Swim threshold 16×200 m
1 h 12 · 4 km
FridayHard
🚴 Bike threshold 3×10min
1 h 10
SundayEasy
Long run 84min
1 h 24 · 13.6 km

Example generated for a intermediate-level profile (VMA 15 km/h, 5 sessions/week). Your plan will depend on your level, availability and feedback.

Your plan, not a template athlete's

This plan is generated for an athlete at intermediate level training 5 times a week. Yours will be calibrated on your VMA, your available days and your feedback after every session. 3 minutes. 14-day trial, cancel anytime.

Create my plan for Half Ironman

Frequently asked questions

How many weeks to prepare for Half Ironman?: For an athlete at intermediate level, Endu builds a 21-week preparation. If your race is closer, the plan compresses phases while keeping the taper; if it's further away, it extends the base phase.
How many sessions per week?: This example has 4.9 sessions per week. You choose 5 to 7 training days and the exact days (e.g. Tue, Thu, Sat, Sun): the plan sticks to them.
Can I follow sessions on my watch?: Yes: every session exports as .fit, the format read by Garmin, Coros, Suunto, Polar and Wahoo. Import it in your watch app and the guided workout appears on your wrist.
How much does it cost?: 14-day free trial, then €7.99/month with no commitment or €59.88/year (€4.99/month). Unlimited objectives and sports.

Useful calculators

Triathlon time calculator CSS calculator (critical swim speed)FTP and power zone calculator Race fuelling calculator

Variations of this plan

By level

Half Ironman beginner Half Ironman advanced

← Half Ironman (70.3) training plan