Half Marathon Training Plan for Beginners
Your first half marathon in 12 weeks. This beginner plan builds the long run progressively, keeps easy days easy, and gets you to 13.1 miles uninjured.
The plan, week by week
Minutes per week. Tap a week.Every version of this plan
The chart above is the one marked “shown”. Ask Claude for any of these and it builds that one, paced from your own runs.
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| Beginners (shown) |
| Your first half |
The half marathon rewards aerobic engine more than raw speed. The runners who struggle most are those who train like 5K runners, carrying too much intensity and not enough easy aerobic volume. Sustainable progression, quality long runs, and one threshold session per week is the formula that holds up across conditions. This plan is built for runners new to running: the structure, pacing guidelines, and weekly progression are calibrated to your specific situation, not a generic template.
How far your longest run should go before a first half marathon
For a first half marathon, the long run is the session that matters most, and it grows slowly. Most beginner plans build it to somewhere between 16 and 19 km, or about two hours of running, two to three weeks before the race. You do not need to cover the full 21.1 km in training: race-day adrenaline and a lighter final fortnight carry you through the last stretch. Add distance every week or two, and drop back for an easier week every third or fourth week. If a long run leaves you limping the next day, repeat that distance before going any further. Slow and steady really is the method here.
Testing your kit on the long runs before a first half
Over two hours or more, small things become big things. Socks that are fine for 30 minutes can blister by 15 km, and a seam that never bothered you can rub skin raw. Use your longest training runs as rehearsals: the shoes, socks, shorts and top you plan to race in, a little anti-chafe balm where things rub, and a way to carry water on warm days. Run some long runs at the time of day your race starts, and eat the breakfast you plan to have on race morning. By race week, nothing you wear or eat should be new. That leaves you free to think about pacing and enjoying it.
Why easy days are your most important sessions
The most counterintuitive thing about starting to run: your easy days are doing more work than you think. Slow aerobic running builds the mitochondrial density, capillary networks, and musculotendinous resilience that form the foundation everything else rests on. Running every session at moderate effort — which feels productive — actually blunts adaptation and raises injury risk. Keep easy days genuinely easy.
The 10% rule and when to break it
The classic guidance is to never increase weekly mileage by more than 10% from one week to the next. It's a useful heuristic, but not sacred. The more important signal is how your body responds: persistent soreness, disrupted sleep, elevated resting heart rate, and loss of motivation are early warning signs that load is outpacing recovery. When in doubt, do less.
What to do when you miss a session
Missing sessions is part of training, not a failure. The worst response is to try to 'make up' a missed run by cramming it into an already-full week — that's how injuries start. If you miss a day, adjust the rest of the week and protect your long run. With Daash, tell Claude what happened and it reworks the rest of the week on your watch, so you never need to guess how to recover.
Training philosophy
The half marathon rewards aerobic engine more than raw speed. The runners who struggle most are those who train like 5K runners, carrying too much intensity and not enough easy aerobic volume. Sustainable progression, quality long runs, and one threshold session per week is the formula that holds up across conditions.
Questions
How many days per week does this half marathon plan require?
Most sessions in this plan run four to five days per week, including one quality session, a long run, and easy aerobic running. The plan is designed to be adjustable — with Daash, Claude can restructure it around your available days each week.
Do I need a GPS watch to follow this half marathon training plan?
A GPS watch or running app is helpful for tracking pace and distance, but not strictly required. Effort-based running (using a scale of 1–10 perceived exertion) works well for easy runs. For quality sessions where specific paces matter, a watch becomes more valuable.
What should I eat before a long run?
For runs under 60–75 minutes, eating beforehand is optional. For longer runs, a light carbohydrate-based meal two to three hours before the session — oats, toast with banana, or a rice-based option — provides fuel without gastrointestinal issues. Avoid high-fat, high-fibre, or unfamiliar foods on long run mornings.
How does Daash adapt the plan if I miss a session?
Daash sees missed sessions in your Garmin data. Tell Claude why — illness, fatigue, life — and it reworks the coming week: redistributing sessions, reducing volume if needed, or adjusting the next quality session, then updates the workouts on your watch.
Is it normal to walk during training runs?
Completely normal — and often strategically correct. For beginner runners, walk-run intervals allow more total time on feet with less injury risk than continuous running. Many elite ultra runners use planned walk intervals even in races. Walking during training runs is not a sign of weakness; it's appropriate load management.
Do I need to take gels or nutrition during training for a half marathon?
For long runs over 75–80 minutes, practising race nutrition is valuable. Train with the gels, chews, or drinks available at your target race so your gut is adapted before race day. Do not try a new nutrition product for the first time on race morning.