A free, complete 16-week half marathon training plan for UK runners. Whether it's your first or your fastest — structured sessions, clear pacing, and a race day strategy that works.
A half marathon is 21.1 kilometres — far enough that pacing and preparation matter enormously, short enough that almost any runner who trains properly can finish one. The difference between a good half marathon experience and a painful one is almost entirely about how you train in the 16 weeks before race day.
⚠️ Before you start: This plan assumes you can already run 5K comfortably without stopping. If you can't, complete the 12-week 5K plan first. Starting a half marathon plan without a base is the leading cause of injury and DNF.
Use your current Parkrun or 5K time to find your target — or use the free race time predictor for a more precise estimate.
| Current 5K time | Half marathon potential | Goal pace (per km) | Easy run pace |
|---|---|---|---|
| 35:00+ | 2:30–3:00 | 7:00–8:30/km | 8:30–10:00/km |
| 30:00–35:00 | 2:10–2:30 | 6:10–7:05/km | 7:30–8:45/km |
| 28:00–30:00 | 2:00–2:10 | 5:41–6:10/km | 6:55–8:00/km |
| 25:00–28:00 | 1:45–2:00 | 4:59–5:41/km | 6:10–7:10/km |
| Sub-25:00 | Sub-1:45 | Sub-4:59/km | 5:45–6:30/km |
The plan runs Monday to Sunday with four running days, two rest or cross-training days, and one full rest day. Long runs are on Sundays. Structure is the same every week — only the distances and intensities change.
Build your base. All runs are easy. The long run starts at 8km and builds to 14km by end of Week 4. No hard sessions — your body is adapting to the training load.
| Week | Tue (Easy) | Thu (Easy) | Sat (Easy) | Sun (Long) | Total |
|---|---|---|---|---|---|
| 1 | 25 min | 30 min | 25 min | 8km easy | ~20km |
| 2 | 30 min | 30 min | 30 min | 10km easy | ~24km |
| 3 | 30 min | 35 min | 30 min | 12km easy | ~27km |
| 4 | 25 min | 25 min | 20 min | 8km easy | ~19km (recovery) |
One tempo session introduced mid-week. Long runs extend to 18km. This phase builds the aerobic engine that carries you through the second half of a half marathon.
| Week | Tue (Easy) | Thu (Tempo) | Sat (Easy) | Sun (Long) | Total |
|---|---|---|---|---|---|
| 5 | 30 min | 10+12+5 min tempo | 35 min | 13km easy | ~30km |
| 6 | 35 min | 10+15+5 min tempo | 35 min | 15km easy | ~34km |
| 7 | 35 min | 10+18+5 min tempo | 35 min | 17km easy | ~37km |
| 8 | 25 min | 30 min easy | 25 min | 10km easy | ~22km (recovery) |
Intervals at half marathon pace introduced. Long runs peak at 19–20km. This is the hardest phase — the sessions are tough but the fitness gain is significant.
| Week | Tue (Easy) | Thu (Intervals) | Sat (Easy/Tempo) | Sun (Long) | Total |
|---|---|---|---|---|---|
| 9 | 35 min | 6 × 1km @ HM pace, 90s rest | 35 min | 16km easy | ~36km |
| 10 | 35 min | 4 × 2km @ HM pace, 2 min rest | 10+15+5 tempo | 18km easy | ~40km |
| 11 | 35 min | 8 × 1km @ HM pace, 75s rest | 40 min easy | 19–20km | ~42km |
| 12 | 30 min | 30 min easy | 25 min | 13km easy | ~27km (recovery) |
Volume reduces. Intensity stays. Your body repairs and consolidates the fitness you've built. Most runners feel sluggish in the taper — this is normal. Trust it.
| Week | Tue | Thu | Sat | Sun |
|---|---|---|---|---|
| 13 | 30 min easy | 5 × 1km @ HM pace | 35 min easy | 18km easy |
| 14 | 30 min easy | 4 × 1km @ HM pace | 30 min easy | 14km easy |
| 15 | 25 min easy | 3 × 1km @ HM pace | 20 min easy | 10km easy |
| 16 | 20 min easy | 15 min + 4 strides | Rest | 🏁 Race Day |
Half marathons are won and lost in the first 5km. The crowd energy and fresh legs make it almost impossible not to go out too fast. Resist this at all costs.
🧪 Test everything in training: Your shoes, your nutrition, your race kit — try all of it on long run days before race day. Nothing new on race day is the most important rule in endurance sport.
The complete plan — every session, every pace, race-day warm-up routine, and nutrition guide — delivered to your inbox.
Want the full annotated PDF with strength work, HR zones, and the marathon plan for when you're ready to step up?
PaceChange Pro — £9.99/month →If you can already run 5K comfortably, 16 weeks is enough time to prepare for a half marathon. If you're starting from scratch, add 8–12 weeks of base building first (use the 5K plan), giving you a total of 24–28 weeks. Rushing the build is the most common cause of half marathon DNS and DNF.
Any finishing time is a good time for a first half marathon — you've covered 21.1km, which most people never do. More specifically: completing a half marathon in under 3 hours is achievable for most beginners who follow a structured plan. The UK average is around 2 hours for male runners and 2:20 for female runners. Sub-2 hours is a solid target for experienced 5K runners stepping up for the first time.
This plan uses four days per week, which is the sweet spot for most working adults. Three days per week is possible but limits improvement. Five or more days per week increases injury risk without proportional benefit for first-time half marathon runners. Quality beats quantity.
No. The long run in this plan peaks at 19–20km — close to but not the full 21.1km. The logic is sound: the taper ensures you arrive at the start line fresh, and the adrenaline of race day carries you through the final kilometre. Running the full distance in training increases recovery time without meaningfully improving fitness.
For first-timers: Great North Run (Newcastle), Bath Half Marathon, and Brighton Half are all well-organised, flat-friendly, and have excellent crowd support. For fast times: Manchester Half Marathon and Reading Half Marathon are reliably flat and fast. Avoid hilly courses like the Richmond Half or Helvellyn for your first attempt.
Related pages: 5K Training Plan · Race Time Predictor · Running Calorie Calculator