Build towards your first half marathon one steady week at a time
A first half marathon can feel daunting when you are fitting training around work, family and recovery. This 12-week outline gives you a repeatable weekly structure, gradually lengthens your long run and eases off before race day.
Treat the plan as a framework, not a test you have to pass. It assumes you can already run continuously for about 30 minutes at an easy effort; if you are not there yet, give yourself extra time and build your running base first. The British Heart Foundation notes that training time depends on your fitness and goal, and estimates that preparing for a half marathon can take three to six months for many people. Its beginner running guidance is a useful reminder that a 12-week block is not the right starting point for everyone.
Is 12 weeks enough for your first half marathon?
This is a reasonable block if you already have a modest running base, but it is not a shortcut from inactivity to 13.1 miles. NHS Charities Together’s beginner plan is designed for runners stepping up to longer distances and assumes you can manage a 30-minute continuous easy run. It schedules three to four sessions a week, with optional core work and cross-training. If you are still building towards that starting point, extend your preparation rather than squeezing the same progression into less time.
A first running challenge progression can also help you decide whether a 5K or 10K is a better next step before committing to a half marathon.
What should a week of training include?
Keep the week simple: one easy run, one shorter session that may include controlled quicker efforts, and one long easy run. Leave rest or low-impact cross-training between demanding sessions. Optional core work or strength training can fit on an easy day, but it should not leave you too tired to complete the key runs.
“Easy” means you can speak in full sentences and finish feeling you could have continued. Do not chase a pace on these runs. The NHS Charities Together plan specifically warns beginners not to make easy sessions too hard; it also uses walking breaks on longer efforts when needed. If you prefer to build distance rather than time, keep the same principle: progress gradually, and do not increase both speed and distance aggressively in the same week.
How can you progress over 12 weeks?
Use the following as a time-based outline, not a rigid prescription. It follows the general pattern in published beginner plans: a gradual long-run build, a peak endurance period, then reduced training before race day. Their exact sessions differ, so adapt the effort and recovery to your current ability.
- Weeks 1–4: Run three times weekly if that is manageable. Keep two runs easy; make the long run about 40 to 75 minutes, using walk breaks if useful. Add a short controlled effort session only if you are recovering well.
- Weeks 5–8: Continue with three runs and gradually extend the long run. One published NHS beginner schedule builds its long effort towards 1 hour 45 minutes by week eight. Do not treat that as a target you must hit if your body is not coping.
- Weeks 9–10: Hold or gently extend endurance, rather than adding a sudden jump. The same NHS plan includes a two-hour long run in week nine, then a shorter 90-minute run in week ten. These are examples from that schedule, not universal requirements.
- Week 11: Reduce the long run and keep other sessions comfortable. Use the week to absorb training rather than trying to gain fitness at the last minute.
- Week 12: Taper: cut back the workload, keep only short easy runs, and rest before the event. The NHS plan uses short runs and rest in race week.
The British Heart Foundation’s beginner half-marathon schedule offers another example of a 12-week structure, with easy efforts, rest, cross-training and a taper. Neither schedule should be treated as a guarantee of finishing or a substitute for adjusting to pain, illness or unusual fatigue.
Should you choose a time-based or distance-based plan?
A time-based plan can be easier to follow if you are new to longer running or do not use a GPS watch. It also helps keep the long run focused on time on your feet rather than an arbitrary pace. A distance-based plan may suit you if you already run regularly and know how your body responds to weekly mileage. Either way, choose one measure and progress conservatively; avoid converting a time schedule into faster running simply to cover more distance.
For a first event, prioritise consistency over a target finish time. If you have a recent 10K or regular easy runs behind you, that experience can help you judge effort, but race pace should not dictate every training session.
How do you handle race week and check that the plan is working?
In the final week, do less rather than trying to squeeze in one last fitness boost. Keep any runs short and easy, leave space for sleep and normal meals, and use familiar shoes and clothing. On race day, start at a pace that feels controlled; walking breaks are a valid way to manage effort if that is part of your approach.
Check progress by looking at recovery as well as pace: are easy runs still comfortable, and are you able to return to normal between sessions? If fatigue keeps building, reduce the workload or take extra rest. The NHS beginner schedule advises substituting cross-training when injured or very sore and taking extra rest when required. If pain is persistent or changes how you move, pause running and seek appropriate clinical advice.
Frequently asked questions
Can I use this plan if I cannot yet run for 30 minutes?
Build up to that comfortable continuous run before starting the 12-week block, or choose a longer preparation period. The NHS Charities Together beginner plan makes a 30-minute easy run its starting assumption. If that currently feels out of reach, shorter run-walk sessions and rest days can help you progress gradually rather than forcing the plan’s early weeks.
Do I need to run the full 13.1 miles before race day?
No. The beginner plans cited here use long runs based on time and build endurance without requiring you to cover the entire race distance in training. Keep your longest session controlled and recover afterwards; the aim is to reach the start prepared, not to prove race distance in advance.
What if I miss a week or feel unusually tired?
Do not try to make up missed sessions by stacking hard runs or suddenly extending the long run. Resume with an easier week if needed, and replace running with rest or gentle cross-training when you are very sore or injured. Persistent or concerning symptoms merit advice from a healthcare professional.