Twelve-Week Half Marathon Training Plan for a Fall Race

Twelve weeks is enough to train for a half marathon if you have a base of three runs a week and a longest run of about six miles. If you have less than that, give yourself sixteen weeks instead. If you have more, you can sharpen the plan for time.

This plan targets a fall half marathon. We built it for the Malad Valley Half on September 12, 2026, but the structure works for any half marathon in September or early October. Start the plan in late June.

The shape of the week

Four runs per week. One long run on Saturday. One easy run on Tuesday. One workout on Thursday. One easy run on Sunday. Take Monday, Wednesday, and Friday as rest or cross training days.

Easy runs are conversational pace. If you cannot say a full sentence, slow down.

Long runs are also easy pace. The goal is time on feet, not speed.

Workouts vary week to week. Some are tempo runs at half marathon pace. Some are intervals at 10K pace. Some are progression runs that start easy and finish fast.

The twelve weeks

Week 1: Easy 3 mi Tue, easy 3 mi Sun, 4 mi with the middle two at tempo Thu, long run 6 mi Sat. Total 16 mi.

Week 2: Easy 3, easy 3, 5 mi with three at tempo, long 7. Total 18.

Week 3: Easy 4, easy 3, 5 mi with four at tempo, long 8. Total 20.

Week 4 (cutback): Easy 3, easy 3, 4 mi easy, long 6. Total 16.

Week 5: Easy 4, easy 3, 6 mi with four at tempo, long 9. Total 22.

Week 6: Easy 4, easy 4, 6×800 at 10K pace with 400 jog recovery (about 7 mi total), long 10. Total 25.

Week 7: Easy 4, easy 4, 7 mi with five at tempo, long 11. Total 26.

Week 8 (cutback): Easy 3, easy 3, 5 mi easy, long 8. Total 19.

Week 9 (peak): Easy 5, easy 4, 8×800 at 10K pace with 400 jog (about 8 mi total), long 12. Total 29.

Week 10: Easy 5, easy 4, 7 mi with five at half marathon pace, long 11. Total 27.

Week 11 (taper start): Easy 4, easy 3, 5 mi with three at half marathon pace, long 8. Total 20.

Week 12 (race week): Easy 3 Tue, easy 2 Wed, easy 2 Thu with 4x100m strides, rest Fri, race Sat.

How to run the workouts

Tempo pace is comfortably hard. If your half marathon goal pace is 9:00 per mile, tempo runs sit around 8:45 per mile. You should be breathing hard but in control. Tempo is not a race effort.

10K pace is faster. If your 10K goal is 50 minutes, that is 8:00 per mile. Run the 800s at that pace. The recoveries are easy jog, not standing rest.

Long runs build slowly. Each long run adds one mile until the cutback week, then resets and climbs again. The longest run is 12 miles. You do not need to run the full 13.1 in training. The race-day adrenaline and tapered legs will carry you the last mile.

Cutback weeks matter as much as build weeks. Every third week, drop the volume by 25 percent. This lets your body absorb the work. Runners who skip the cutbacks get hurt by week eight.

Around the runs

Cross training on the off days helps. Easy bike rides, swims, or walks. Strength work twice a week is gold. Squats, lunges, single-leg deadlifts, planks. Twenty minutes is enough.

Sleep eight hours when you can. Eat carbs the day before long runs. Drink water all day, every day.

If you get sick or hurt, take the days off and pick up where the calendar says. Do not try to make up missed long runs. The plan has built-in flex.

Race day

Eat your usual breakfast two to three hours before the gun. Get to the start early. Pee twice. Stay warm. Plan to run the first three miles ten to twenty seconds per mile slower than goal pace. Settle in. Pick up the pace in the middle miles. Race the last 5K.

If your goal is to finish, run the first ten miles easy and let the last 5K take care of itself. If your goal is a time, hold the pace through mile ten and then commit to the last 5K like you mean it.

The Malad Valley Half rolls on quiet country roads in southeast Idaho. Cool morning, big sky, friendly aid stations. Train through the summer and we will see you at the start September 12, 2026.