12-Week Jacksonville Marathon Training Plan

Jacksonville, FLDecember 12, 2026

Start around September 19, 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
September 19, 2026
Runway
12 weeks
Course
Very Flat · Out and Back
Plan choice
Current training

Does this window fit your starting point?

Use this window when your recent training is steady and the opening week will not be a mileage jump. If you are returning after a long break, twelve weeks is too little room to rebuild and peak at the same time.

  • Your weekly mileage has been consistent for the last six to eight weeks.
  • You have completed recent long runs and do not need to rebuild from three easy miles.
  • You can protect the same number of run days from week one through race week.
  • You are prepared to begin race-specific work early instead of using a long base phase.

The 12-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.

Settle

Weeks 1–2

Sep 20, 2026–Oct 3, 2026

Hold close to your current volume, establish the weekly rhythm, and make sure the opening load is honest.

Build

Weeks 3–7

Oct 4, 2026–Nov 7, 2026

Grow the long run and weekly work with step-back weeks intact. There is no room to repay missed mileage.

Peak

Weeks 8–10

Nov 8, 2026–Nov 28, 2026

Complete the most race-specific long runs, rehearse fueling, and practice the terrain that will decide the final 10K.

Taper

Weeks 11–12

Nov 29, 2026–Dec 12, 2026

Reduce volume, keep the routine familiar, and arrive on race day without trying to squeeze in one more big week.

Make the window specific to Jacksonville Marathon.

Course-specific work starts early in a 12-week build. Put the race's terrain and expected conditions into long runs once the opening weeks feel controlled, without adding extra hard days.

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

12-week Jacksonville Marathon plan questions, answered.

When should I start a 12-week Jacksonville Marathon plan?

The 2026 Jacksonville Marathon is scheduled for December 12, 2026, so the 12-week window opens around September 19, 2026. Treat that as the outside edge of the window, then line week one up with the plan's normal weekly rhythm.

Is a 12-week plan long enough for the Jacksonville Marathon?

Use this window when your recent training is steady and the opening week will not be a mileage jump. If you are returning after a long break, twelve weeks is too little room to rebuild and peak at the same time. 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 12 weeks?

Course-specific work starts early in a 12-week build. Put the race's terrain and expected conditions into long runs once the opening weeks feel controlled, without adding extra hard days. 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 12-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 12-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.