4-Day Boise River Marathon Training Plan

Boise, IDMay 2, 2027

Four runs per week for 18 weeks: two easy runs, one midweek aerobic run, and one long run. The schedule stays fixed; the guidance below shows how to choose terrain, rehearse conditions, and prepare for the Boise River Marathon course.

The Boise River Marathon is 26.2 miles of paved riverside path, out and back, with 283 finishers in 2026. The race describes its own course as flat, fast and scenic, following the Boise River from a rocky canyon into the middle of the city before turning you around to run all of it again in reverse.

See the full 18-week plan Read the full race guide

Race day: May 2, 2027
18-week window: Around December 27, 2026
Course: Rolling Hills · Out and Back
Peak week: 40 miles
Longest run: 20 miles

Your complete Boise River Marathon schedule

The 18-week window opens around December 27, 2026. Weeks one through 17 keep the normal Tuesday, Wednesday, Thursday, and Sunday rhythm. Only race week moves so the marathon lands on its actual weekday. If the window has passed, do not skip ahead or cram missed mileage into the time left.

Open any week to see all seven days. Week 1 is open to start.

1Week 1Foundation · 15 mi

Mon

Rest

Tue

Easy

3 mi easy run

Wed

Cross-training

30 min easy cross-training or mobility

Thu

Easy

3 mi relaxed aerobic run

Fri

Rest

Sat

Easy

3 mi easy run

Sun

Long run

6 mi long run, conversational effort

2Week 2Foundation · 17 mi

Mon

Rest

Tue

Easy

3 mi easy run

Wed

Cross-training

30 min easy cross-training or mobility

Thu

Easy

4 mi relaxed aerobic run

Fri

Rest

Sat

Easy

3 mi easy run

Sun

Long run

7 mi long run, conversational effort

3Week 3Recovery week · 15 mi

Mon

Rest

Tue

Easy

3 mi easy run

Wed

Cross-training

Rest or 20 min gentle mobility

Thu

Easy

3 mi relaxed aerobic run

Fri

Rest

Sat

Easy

3 mi easy run

Sun

Long run

6 mi long run, conversational effort

4Week 4Build · 19 mi

Mon

Rest

Tue

Easy

3 mi easy run

Wed

Cross-training

30–40 min easy cross-training

Thu

Easy

5 mi relaxed aerobic run

Fri

Rest

Sat

Easy

3 mi easy run + 4 relaxed strides

Sun

Long run

8 mi long run, conversational effort

5Week 5Build · 22 mi

Mon

Rest

Tue

Easy

4 mi easy run

Wed

Cross-training

30–40 min easy cross-training

Thu

Easy

5 mi relaxed aerobic run

Fri

Rest

Sat

Easy

3 mi easy run

Sun

Long run

10 mi long run; practice fluids

6Week 6Recovery week · 18 mi

Mon

Rest

Tue

Easy

3 mi easy run

Wed

Cross-training

Rest or 25 min gentle cross-training

Thu

Easy

4 mi relaxed aerobic run

Fri

Rest

Sat

Easy

3 mi easy run

Sun

Long run

8 mi long run, conversational effort

7Week 7Build · 25 mi

Mon

Rest

Tue

Easy

4 mi easy run

Wed

Cross-training

30–40 min easy cross-training

Thu

Quality

6 mi steady run; final 1 mi at planned marathon effort

Fri

Rest

Sat

Easy

3 mi easy run

Sun

Long run

12 mi long run; practice fuel and fluids

8Week 8Recovery week · 23 mi

Mon

Rest

Tue

Easy

4 mi easy run

Wed

Cross-training

30 min easy cross-training or mobility

Thu

Easy

5 mi relaxed aerobic run

Fri

Rest

Sat

Easy

4 mi easy run + 4 relaxed strides

Sun

Long run

10 mi long run, conversational effort

9Week 9Build · 29 mi

Mon

Rest

Tue

Easy

4 mi easy run

Wed

Cross-training

30–40 min easy cross-training

Thu

Quality

7 mi steady run; middle 2 mi at planned marathon effort

Fri

Rest

Sat

Easy

4 mi easy run

Sun

Long run

14 mi long run; use race-day fuel timing

10Week 10Recovery week · 24 mi

Mon

Rest

Tue

Easy

4 mi easy run

Wed

Cross-training

Rest or 25 min gentle cross-training

Thu

Easy

5 mi relaxed aerobic run

Fri

Rest

Sat

Easy

4 mi easy run

Sun

Long run

11 mi long run, conversational effort

11Week 11Build · 32 mi

Mon

Rest

Tue

Easy

5 mi easy run

Wed

Cross-training

30–40 min easy cross-training

Thu

Quality

7 mi steady run; final 2 mi at planned marathon effort

Fri

Rest

Sat

Easy

4 mi easy run

Sun

Long run

16 mi long run; rehearse fuel, fluids, and kit

12Week 12Recovery week · 26 mi

Mon

Rest

Tue

Easy

4 mi easy run

Wed

Cross-training

Rest or 25 min gentle cross-training

Thu

Easy

6 mi relaxed aerobic run

Fri

Rest

Sat

Easy

4 mi easy run + 4 relaxed strides

Sun

Long run

12 mi long run, conversational effort

13Week 13Peak week · 36 mi

Mon

Rest

Tue

Easy

5 mi easy run

Wed

Cross-training

30 min easy cross-training or mobility

Thu

Quality

8 mi steady run; middle 3 mi at planned marathon effort

Fri

Rest

Sat

Easy

5 mi easy run

Sun

Long run

18 mi long run; full race-day fueling rehearsal

14Week 14Recovery week · 29 mi

Mon

Rest

Tue

Easy

5 mi easy run

Wed

Cross-training

Rest or 25 min gentle cross-training

Thu

Easy

6 mi relaxed aerobic run

Fri

Rest

Sat

Easy

4 mi easy run

Sun

Long run

14 mi long run, conversational effort

15Week 15Peak week · 40 mi

Mon

Rest

Tue

Easy

6 mi easy run

Wed

Cross-training

30 min easy cross-training or mobility

Thu

Quality

9 mi steady run; middle 4 mi at planned marathon effort

Fri

Rest

Sat

Easy

5 mi easy run

Sun

Long run

20 mi long run; complete race-day rehearsal

16Week 16Taper · 26 mi

Mon

Rest

Tue

Easy

4 mi easy run

Wed

Cross-training

25 min easy cross-training or mobility

Thu

Quality

6 mi relaxed run; 2 mi at planned marathon effort

Fri

Rest

Sat

Easy

4 mi easy run

Sun

Long run

12 mi long run, controlled effort

17Week 17Taper · 18 mi

Mon

Rest

Tue

Easy

3 mi easy run

Wed

Cross-training

Rest or 20 min gentle mobility

Thu

Easy

4 mi relaxed run + 4 short strides

Fri

Rest

Sat

Easy

3 mi easy run

Sun

Long run

8 mi long run, conversational effort

18Week 18Taper · 8 mi + race

Mon

Rest

Tue

Easy

3 mi easy run

Wed

Rest

Rest or 15 min gentle mobility

Thu

Easy

3 mi easy run + 4 short strides

Fri

Rest

Sat

Easy

2 mi shakeout, or rest

Sun

Race

Marathon — 26.2 mi

Week	Mon	Tue	Wed	Thu	Fri	Sat	Sun	Run total
Week 1Foundation	Rest	3 mi easy run	30 min easy cross-training or mobility	3 mi relaxed aerobic run	Rest	3 mi easy run	6 mi long run, conversational effort	15 mi
Week 2Foundation	Rest	3 mi easy run	30 min easy cross-training or mobility	4 mi relaxed aerobic run	Rest	3 mi easy run	7 mi long run, conversational effort	17 mi
Week 3Recovery week	Rest	3 mi easy run	Rest or 20 min gentle mobility	3 mi relaxed aerobic run	Rest	3 mi easy run	6 mi long run, conversational effort	15 mi
Week 4Build	Rest	3 mi easy run	30–40 min easy cross-training	5 mi relaxed aerobic run	Rest	3 mi easy run + 4 relaxed strides	8 mi long run, conversational effort	19 mi
Week 5Build	Rest	4 mi easy run	30–40 min easy cross-training	5 mi relaxed aerobic run	Rest	3 mi easy run	10 mi long run; practice fluids	22 mi
Week 6Recovery week	Rest	3 mi easy run	Rest or 25 min gentle cross-training	4 mi relaxed aerobic run	Rest	3 mi easy run	8 mi long run, conversational effort	18 mi
Week 7Build	Rest	4 mi easy run	30–40 min easy cross-training	6 mi steady run; final 1 mi at planned marathon effort	Rest	3 mi easy run	12 mi long run; practice fuel and fluids	25 mi
Week 8Recovery week	Rest	4 mi easy run	30 min easy cross-training or mobility	5 mi relaxed aerobic run	Rest	4 mi easy run + 4 relaxed strides	10 mi long run, conversational effort	23 mi
Week 9Build	Rest	4 mi easy run	30–40 min easy cross-training	7 mi steady run; middle 2 mi at planned marathon effort	Rest	4 mi easy run	14 mi long run; use race-day fuel timing	29 mi
Week 10Recovery week	Rest	4 mi easy run	Rest or 25 min gentle cross-training	5 mi relaxed aerobic run	Rest	4 mi easy run	11 mi long run, conversational effort	24 mi
Week 11Build	Rest	5 mi easy run	30–40 min easy cross-training	7 mi steady run; final 2 mi at planned marathon effort	Rest	4 mi easy run	16 mi long run; rehearse fuel, fluids, and kit	32 mi
Week 12Recovery week	Rest	4 mi easy run	Rest or 25 min gentle cross-training	6 mi relaxed aerobic run	Rest	4 mi easy run + 4 relaxed strides	12 mi long run, conversational effort	26 mi
Week 13Peak week	Rest	5 mi easy run	30 min easy cross-training or mobility	8 mi steady run; middle 3 mi at planned marathon effort	Rest	5 mi easy run	18 mi long run; full race-day fueling rehearsal	36 mi
Week 14Recovery week	Rest	5 mi easy run	Rest or 25 min gentle cross-training	6 mi relaxed aerobic run	Rest	4 mi easy run	14 mi long run, conversational effort	29 mi
Week 15Peak week	Rest	6 mi easy run	30 min easy cross-training or mobility	9 mi steady run; middle 4 mi at planned marathon effort	Rest	5 mi easy run	20 mi long run; complete race-day rehearsal	40 mi
Week 16Taper	Rest	4 mi easy run	25 min easy cross-training or mobility	6 mi relaxed run; 2 mi at planned marathon effort	Rest	4 mi easy run	12 mi long run, controlled effort	26 mi
Week 17Taper	Rest	3 mi easy run	Rest or 20 min gentle mobility	4 mi relaxed run + 4 short strides	Rest	3 mi easy run	8 mi long run, conversational effort	18 mi
Week 18Taper	Rest	3 mi easy run	Rest or 15 min gentle mobility	3 mi easy run + 4 short strides	Rest	2 mi shakeout, or rest	Marathon — 26.2 mi	8 mi + race

This free plan is complete, fixed, and ready to use.

It begins at 15 miles per week, peaks at 40, and asks you to manage schedule changes and missed training yourself.

A Stride plan ranks from your running, then dates to race day.

Current mileage, recent longest run, marathon experience, goal, and available days decide which plans rank first.

Build My Plan

How to use this plan for Boise River Marathon

The mileage builds your engine. Your long-run route, pacing, fueling, and clothing rehearsals make that fitness specific to this race.

How to train for the Boise River Marathon

Train for the Boise River Marathon by building tolerance for repetition. The most useful sessions are long runs on a flat paved path, solo, at goal effort, with no company and nothing to look at, because that's exactly what race day is. Learn what your goal pace feels like when nothing outside you changes for hours.

Then protect your legs from that repetition. Add short hill repeats or gentle strides on grass once a week, not because the course has hills but because varying your stride angle keeps calves and hip flexors from grinding down over a whole training block of flat path running.

Last, rehearse the turnaround. Run a long out and back where you deliberately hold something back on the way out, so that seeing the halfway cone feels like a start rather than a verdict.

Keep the plan honest. This free schedule contains no speedwork. Apply the course guidance through route choice and race rehearsal without turning easy days into extra workouts. If your goal calls for marathon-pace work, compare it with First Marathon Plus.

Match the terrain

Run part of your Boise River Marathon long-run mileage on terrain that rises and falls. Hold effort steady on climbs, let pace change, and practice cresting without surging.

Rehearse race morning

Early May in Boise averages a high of 69F and a low of 44F, so the 6:30 a.m. start is doing real work for you. No start line temperature is published for this race, but the pattern is a cool start and a finish that warms up fast for anyone out past four hours. Do a few late winter long runs in the warmest part of the day so a 60s finish isn't a surprise.

Prepare for the hard part

Miles 20 to 26 on the return leg, where the path is flat, familiar and empty, and there's no terrain change to hide behind.

Check the starting line before you commit.

Beginner-friendly does not mean couch-to-marathon. Week one asks for four runs, 15 total miles, and a six-mile long run.

Fifteen miles in week one is close to the volume you already handle.
You can protect four run days most weeks, including a weekend long run.
Your priority is a steady first-marathon build without speedwork.
You can start around December 27, 2026 without forcing the early weeks.

Boise River Marathon course facts

Course: Out and Back · Rolling Hills · Road/Pavement
Marathon finishers: 283 in 2026 (very small field)
Boston qualifier: Not a certified Boston qualifying course
Race day high / low: 69°F / 44°F on average

Sources

Boise River Marathon questions, answered.

When should I start this 18-week Boise River Marathon plan?

The 2027 Boise River Marathon is scheduled for May 2, 2027, so the 18-week window opens around December 27, 2026. Weeks one through 17 keep the normal weekly rhythm and Sunday long run; only the final race week shifts to the event's actual weekday. If that date has already passed, do not compress 18 weeks of mileage into a shorter window.

How should I adapt the four-day plan for the Boise River Marathon course?

Run part of your Boise River Marathon long-run mileage on terrain that rises and falls. Hold effort steady on climbs, let pace change, and practice cresting without surging. Train for the Boise River Marathon by building tolerance for repetition. The most useful sessions are long runs on a flat paved path, solo, at goal effort, with no company and nothing to look at, because that's exactly what race day is. Learn what your goal pace feels like when nothing outside you changes for hours.

Is four days a week enough to train for the Boise River Marathon?

Four run days can be enough when 15 miles in week one is not a sudden jump and you can protect the long run most weeks. This schedule builds to a 40-mile peak and a 20-mile long run. A runner chasing an aggressive time or already supporting more volume may fit a higher-mileage plan better.

Is the Boise River Marathon flat?

The race calls its course flat, fast and scenic, following the Boise River on paved path. Some race listings label the profile as rolling, which is a mismatch worth knowing about, and no elevation figures are published for the course. Either way, this is not a hilly marathon and there's no signature climb to train for.

Is the Boise River Marathon a good first marathon?

Yes. A flat paved out and back with hydration roughly every two miles and a 6:30 a.m. start removes most of what goes wrong in a first marathon. The main challenge is solitude: 283 people finished in 2026, so practice long runs alone at goal effort before race day.

The same four-day schedule, shaped around the course ahead.

Choose your race for its current date, course profile, typical race-morning conditions, and specific long-run guidance.