Running · 6 min read

Half marathon training plan for beginners: 12 weeks, 3 runs a week

Short answer: if you can run 5 km, you can be ready for a half marathon in 12 weeks with three runs a week: an easy run, one faster session and a long run. The long run grows by at most 2 km a week, from 6 km to 17 km two weeks before race day, with lighter weeks in weeks 4 and 8 and a two-week taper.

Who this plan is for

You can already run about 5 km without stopping, even slowly, and you want to finish your first half marathon (21.1 km) feeling good. You have three days a week: here Tuesday and Thursday after work and Sunday morning, but any three days with a rest day between them work.

If 5 km is still out of reach, start with run-walk sessions (for example 2 minutes running, 1 minute walking) for a few weeks, then begin week 1.

How the plan works

• Easy run (Tuesday). Slow enough to talk in full sentences. This is where most of your fitness comes from.
• Quality session (Thursday). Intervals, tempo blocks or hills. Short, controlled efforts teach your body to run faster for longer.
• Long run (Sunday). The heart of the plan. It grows by at most 2 km a week, because big jumps are the most common way beginners get injured.
• Cut-back weeks (4 and 8). About 25% less, so your body can absorb the training. The week after picks up where you were.
• Taper (weeks 11 and 12). Less running, a little speed, and rest the day before the race. You arrive fresh instead of tired.

The full 12-week plan

Warm up with 5 to 10 minutes of easy jogging or brisk walking before every run, and cool down the same way.

Tips that make the difference

• Go slower than you think. If you can't talk, you're running too fast for an easy or long run.
• Practise race day on long runs. Same shoes, same breakfast, and from about 12 km a drink or gel every 40 to 45 minutes.
• Missed a run? Skip it and carry on. Missed a week? Repeat the last full week instead of jumping ahead.
• Pain that changes how you run is a reason to stop, not to push through. Rest two days; if it stays, see a doctor or physiotherapist.
• Race day: start slower than you want to for the first 5 km. Most first-timers who struggle went out too fast.

How this plan was made

This plan was built by the Dots, the AI assistants in Tudots, from one sentence: “Make me a half marathon training plan for a beginner who can already run 5 km. I can run Tuesday, Thursday and Sunday. The race is in 12 weeks.” The app keeps the long run on a safe ladder, so it never jumps. Tell them your own days, level and race date, and you get your own version, already in your calendar.

Frequently asked questions

Can a beginner train for a half marathon in 12 weeks?

Yes, if you can already run about 5 km without stopping. Twelve weeks with three runs a week is enough to build your long run step by step to 16 to 18 km. If 5 km is still hard, spend 4 to 6 weeks getting there first, with run-walk sessions.

How many days a week should I run?

Three is enough for a first half marathon: one easy run, one quality session (intervals, tempo or hills) and one long run. More days help, but rest days are when your body adapts.

How long should my longest run be before a half marathon?

For beginners, 16 to 18 km, about two to three weeks before race day. You don't need to run the full 21.1 km in training; race-day adrenaline and the taper carry you the rest of the way.

How fast should I run the long run?

Slow enough to talk in full sentences. Most beginners run their long runs too fast. If you're breathing too hard to talk, slow down or take a short walk break.

What if I miss a week?

Don't try to catch up. Repeat the last week you completed, then continue. Skipping one or two sessions won't ruin your race; jumping ahead too fast is what causes injuries.

Is it okay to walk during a half marathon?

Yes. Planned walk breaks, for example one minute every 2 to 3 km, are a proven way for beginners to finish strong. Practise them on your long runs first.

This guide is general information, not medical advice. If you have a health condition, are returning from injury or are unsure whether running is right for you, talk to a doctor first.

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