Half Marathon Training Plan — 12 Weeks to Your Goal, Finish or PB

21.1 kilometres is the perfect distance: long enough to demand respect, short enough that with sensible training it is within reach for almost anyone. The difference between a good and a bad half marathon rarely lies on race day — it lies in the twelve weeks before it.

This plan gives you a complete 12-week structure, in two tracks: one for everyone who wants to finish their first half marathon, and one for runners with a time goal. Both follow the same principles — they differ in pace, volume and the intensity of the hard sessions.

Two tracks, one principle

Before you place yourself: the difference between the tracks is not „more is better“. Both build on the same foundation — lots of easy running, little hard running, one long run per week.

Track A — Finish. Your goal is the finish line, not the clock. Three runs per week are enough. The long run is the key session; tempo work only in homeopathic doses. Prerequisite: you can currently run about 30 minutes easy without stopping.

Track B — Time goal. You have already finished a half marathon or a few 10Ks and want a certain time (say sub 2:00 or sub 1:45). Four to five sessions per week, with structured tempo and threshold work. Prerequisite: you have been running regularly for a few months and can manage 60 minutes without stopping.

The four building blocks

Every week in both tracks is made up of the same session types:

The long run is the centrepiece. Easy, in the lower aerobic range (Zone 2), steadily increased. It builds the endurance that carries you over the 21 kilometres. Pace here is explicitly secondary — running the long run too fast sabotages recovery for the rest of the week.

The easy run fills up the volume. Comfortable, enjoyable, at a pace where you could still hold a conversation. These runs feel almost too easy — that is the point.

The tempo session (only relevant in Track B, heavily reduced in Track A) brings the intensity: threshold runs, tempo intervals, and towards the end sections at race pace. This is where the speed comes from.

Recovery is the invisible fourth session. Rest days are not a gap, but the moment when adaptation happens. Skip them, and you train harder and get slower.

The 12-week structure

The twelve weeks fall into four phases:

Weeks 1–4: Base. Build volume slowly, get the body used to regular running. The long run grows gently. No hard work yet — foundation first.

Weeks 5–8: Development. Volume keeps rising, and in Track B structured tempo work comes in. The long run reaches its critical length. This is the most demanding phase.

Weeks 9–10: Specificity. Race pace is rehearsed. The long run contains (Track B) sections at goal pace, so body and mind learn how race pace feels over distance.

Weeks 11–12: Tapering. Volume is reduced sharply, intensity partly kept. The legs get fresh without losing form. The key to a good race day.

Track A — Finish (3 sessions/week)

Rough structure per week: one long run, two easy runs, with rest or alternative days in between (cycling, swimming, strength).

In Track A, the long run does not need to reach the full race distance — 16 to 17 kilometres in training is enough. The remaining kilometres are carried on race day by the atmosphere and the taper.

Track B — Time goal (4–5 sessions/week)

Structure per week: one long run, one tempo session, one to two easy runs, one optional easy extra run.

The time figures for the tempo sessions refer to your threshold pace, not to absolute values. Someone aiming for sub 2:00 runs the same structures as someone at sub 1:30 — just at their own pace. That is exactly why the same plan works for very different target times.

Race day

Pacing is everything. The most common mistake in a half marathon is starting too fast. The first kilometres feel easy — until suddenly they are not. Split the race: first half controlled, slightly under goal pace; second half catch up if there is still something left. An evenly or negatively split race is almost always faster than a euphoric false start.

Fuelling. For a half marathon under about 90 minutes, water is usually enough. If you are out longer, 30 to 60 grams of carbohydrate help — but only what you have tested in training. Never anything new on race day.

Warm-up. Track A: an easy jog is enough. Track B with a time goal: 10–15 minutes easy plus a few strides, so you are on pace from the gun.

Conclusion

A half marathon does not succeed through individual hero sessions, but through twelve weeks of consistent, mostly easy work with one long run as the anchor. Whether you want to finish or run a time changes the dose, not the principle: lots easy, little hard, increase steadily, taper cleanly. Stick to the 10 percent rule, respect the rest days — and race day becomes the reward, not the exam.

Frequently asked questions

How many times per week do I need to run?

For the finisher track, three runs per week are enough. If you are chasing a time, plan four to five. More is not automatically better — consistency beats volume.

Do I need to run the full distance in training?

No. 16 to 18 kilometres as your longest run is enough. Tapering and race-day atmosphere carry you over the rest. Running the full distance beforehand costs more recovery than it gives.

What if I miss a week due to illness?

No drama. Return with reduced volume and do not try to make up the missed progression all at once. A few days off cost less than a dragged-out injury.

How fast should the long run be?

Easy — in the lower aerobic range, where you could still hold a conversation. The long run builds endurance, not speed. Run too fast, and it sabotages recovery for the rest of the week.

Can I add cycling or swimming?

Yes, as easy cross-training on non-running days — joint-friendly and good for aerobic base. But it does not replace the long run or the tempo session.