20-Week Jacksonville Marathon Training Plan

Jacksonville, FLDecember 12, 2026

Start around July 25, 2026. The calendar below gives each phase a real date, then the course guidance shows where to make the build specific to Jacksonville Marathon.

The Jacksonville Marathon is about as flat as a road marathon gets. The entire course sits between roughly 5 and 29 feet above sea level, with about 219 feet of cumulative climb and 220 feet of descent across all 26.2 miles, which nets out to a single foot. It is run as an out and back in mid December, and 703 people finished it in 2025.

Race day
December 12, 2026
Start window
July 25, 2026
Runway
20 weeks
Course
Very Flat · Out and Back
Plan choice
Current training

Does this window fit your starting point?

Use the longer window to make the early build calmer, not to add five months of hard training. The plan should begin close to your current load, hold most running easy, and delay the biggest race-specific work until the middle of the cycle.

  • You want a longer foundation phase before marathon-specific training.
  • Your current mileage is steady but below the load you expect to carry later.
  • You prefer gradual long-run growth with regular step-back weeks.
  • You can sustain a five-month routine without turning every week into a peak week.

The 20-week Jacksonville Marathon calendar

These dates define the job of each phase. Your current mileage, recent longest run, experience, goal, and available days still decide the actual workouts inside them.

Foundation

Weeks 1–6

Jul 26, 2026–Sep 5, 2026

Set the routine, grow easy volume gradually, and finish each week with enough control to repeat it.

Build

Weeks 7–13

Sep 6, 2026–Oct 24, 2026

Extend the long run, introduce race-specific terrain, and keep recovery weeks on the calendar.

Peak

Weeks 14–17

Oct 25, 2026–Nov 21, 2026

Complete the most demanding race rehearsals and settle fueling, pacing, shoes, and clothing before taper begins.

Taper

Weeks 18–20

Nov 22, 2026–Dec 12, 2026

Reduce the load, keep familiar running in the week, and let the work from the previous four months show up on race day.

Make the window specific to Jacksonville Marathon.

Build general durability first. Add the race's hills, flat sustained running, downhill exposure, heat, or humidity in layers after the weekly rhythm is stable, then make the final long runs the most course-specific.

Read the full race guide

How to train for the Jacksonville Marathon

Train for the Jacksonville Marathon the way you would train for a track race stretched out over 26 miles: even effort, even cadence, no surges. With 24 feet of vertical range there is no terrain to force a change of gear, so your long runs should be flat, continuous, and run at a pace you could hold for another 45 minutes when you finish. Practicing restraint is the workout.

The specific cost of flat ground is repetition, not effort. Same muscles, same joint angles, same footstrike, for the entire race. Build a strength routine that covers what the course will not: single leg loading, calf and soleus work, and some hill or stair repeats even though the race has none, purely so your legs have been asked to do something else recently.

Then plan around the calendar. A December race means your build runs through late summer and autumn, and race morning in Jacksonville is usually humid even when it is cool. Do a meaningful share of your long runs in humid air, and pin down your fluid plan in those conditions rather than in a dry October week.

Finally, use the turnaround as a training cue. In two or three of your long runs, go out to a fixed point and come back, with a rule that the return half is run faster than the first. That builds the pacing habit the shape of this course rewards.

Jacksonville Marathon course facts

Course
Out and Back · Very Flat · Road/Pavement
Elevation gain / loss
219 ft gain, 220 ft loss
Highest / lowest point
29 ft / 5 ft
Marathon finishers
703 in 2025 (small field)
Boston qualifier
Certified Boston qualifying course
Finishers running a qualifying time
14.4% in 2025
Typical race morning
57°F at the start, 88% humidity, overcast
Race day high / low
61°F / 44°F on average

Sources

Let your current training decide the actual plan.

Current mileage, recent longest run, marathon experience, goal, and available days determine which plans rank first. After you choose and subscribe, Stride dates every workout through December 12, 2026.

Build My Plan

20-week Jacksonville Marathon plan questions, answered.

When should I start a 20-week Jacksonville Marathon plan?

The 2026 Jacksonville Marathon is scheduled for December 12, 2026, so the 20-week window opens around July 25, 2026. Treat that as the outside edge of the window, then line week one up with the plan's normal weekly rhythm.

Is a 20-week plan long enough for the Jacksonville Marathon?

Use the longer window to make the early build calmer, not to add five months of hard training. The plan should begin close to your current load, hold most running easy, and delay the biggest race-specific work until the middle of the cycle. The course does not change the opening load you can handle, so choose from your current mileage and recent longest run before adding race-specific terrain.

How should I prepare for the Jacksonville Marathon course in 20 weeks?

Build general durability first. Add the race's hills, flat sustained running, downhill exposure, heat, or humidity in layers after the weekly rhythm is stable, then make the final long runs the most course-specific. Train for the Jacksonville Marathon the way you would train for a track race stretched out over 26 miles: even effort, even cadence, no surges. With 24 feet of vertical range there is no terrain to force a change of gear, so your long runs should be flat, continuous, and run at a pace you could hold for another 45 minutes when you finish. Practicing restraint is the workout.

What if the 20-week Jacksonville Marathon window has already started?

Do not double weeks or cram missed mileage into the remaining calendar. Use your current mileage, recent longest run, experience, goal, and available days to choose a plan that can enter at an appropriate point while preserving the taper.

How flat is the Jacksonville Marathon?

Extremely. The whole course sits between roughly 5 and 29 feet above sea level, and it accumulates about 219 feet of climb and 220 feet of descent over the full 26.2 miles, for a net change of one foot. There is no hill anywhere on it, only camber and drainage.

Is the Jacksonville Marathon a good Boston qualifier?

It is a solid one. The course is certified and 14.4% of finishers ran a Boston qualifying time in 2025, after 11.4% in 2024 and 9.4% in 2023. Because the course has effectively no net drop, no downhill adjustment applies to times run there, so what you run is what counts.

Put the 20-week window against your actual race.

Each page counts back from race day, maps the 4 phases to real dates, and applies the window to that course and its typical conditions.