Half Marathon Training Plan: 8, 10, 12 or 16 Weeks
A half marathon plan in four lengths, 8 to 16 weeks. The classic is 12: progressive long runs, two quality sessions a week and a proper two-week taper.
The plan, week by week
Minutes per week. Tap a week.Pick your plan length
The chart above is the one marked “shown”. Ask Claude for any of these and it builds that one, paced from your own runs.
| Version | Weeks | Weeks of each phase |
|---|---|---|
| 8 weeks | 8 | 2 base · 3 build · 1 sharpen · 2 race |
| 10 weeks | 10 | 3 base · 4 build · 1 sharpen · 2 race |
| 12 weeks (shown) | 12 | 4 base · 4 build · 1 peak · 3 taper |
| 16 weeks | 16 | 5 base · 5 build · 3 peak · 3 taper |
A 12-week half marathon training plan designed for runners with a clear goal and a defined timeline. 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.
Choosing a half marathon block length
Pick the block length from where you are now, not from the race date alone. If you already run four or five times a week with a long run of 75 minutes or more, a shorter block is enough. If your long run is under an hour, or your running has been patchy, the longer block gives the long run time to grow safely to the 16 to 20 km most half marathon plans reach. The extra weeks also leave room for a missed week without the whole plan falling apart.
The phases of a medium-length training block
A 12-week plan splits into 4 phases: 4 weeks of base, 4 of build, 1 at peak and a 3-week taper. Understanding which phase you're in helps you interpret what the sessions are trying to accomplish.
Building progressive overload safely
Medium-length training blocks allow for proper periodisation: load builds over three weeks, drops on the fourth recovery week, then builds again from a higher baseline. Never skip recovery weeks — they're when adaptation happens. The recovery week feels like a step backward but delivers a step forward.
Race-week management
The final week before race day is about feeling fresh, not building fitness — that work is done. Keep sessions short, maintain intensity with one or two race-pace efforts of 60–90 seconds, stay off your feet more than usual, and sleep aggressively. The taper itch (restlessness, phantom soreness, doubt) is normal and almost always resolves on race morning.
Who this plan is for
An 8-week half marathon plan assumes you already have a running base — at minimum, you should be running 3–4 days per week and comfortable with a 45-60 minute easy run. This is not a start-from-zero plan. The condensed timeline means every session is purposeful, and recovery is non-negotiable.
How to make the most of a short block
Short training cycles demand higher session quality and ruthless prioritisation. If you can only hit three out of four sessions in a week, protect the quality session and the long run. Easy runs are the most disposable in a compressed block. Do not add volume beyond what's prescribed — with limited time, more is not better.
What to expect at the finish line
8 weeks is enough to meaningfully improve half marathon performance for a runner with existing base. You won't build all the aerobic infrastructure of a longer block, but you will sharpen pace, improve efficiency, and arrive race-ready. Set a realistic goal based on recent race times, not your best-ever performance.
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.
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.