First Marathon training plan,
on your Garmin.
Your first marathon has exactly one goal, and it is to finish it in a state you would describe as human. Time goals belong to your second one. That single decision changes the whole plan: lower volume, more weeks, no hero sessions, and a great deal more patience than most first-timers want.
What a first marathon week looks like
Build length: 20 to 24 weeks, including base building
Weekly volume: 45 to 70 km a week, nearly all of it easy
Four runs. A long run building slowly to around 30 km, one steady run, two easy runs, and genuine rest days that you actually take.
The session that decides your first marathon
The progressively longer easy long run. No pace work at all. Time on feet is the entire adaptation you are chasing, and adding intensity on top is how first-timers get injured.
The mistake almost everyone makes
Fuelling for a first marathon
Learn it now, on every single long run. A first marathon is slow enough that you will be out there a long time, which means more fuel and more chances for your stomach to object. Start at 40 to 60 grams an hour.
Which Garmin metrics actually matter here
- Heart-rate zones, so the long run stays genuinely easy
- Body Battery, as a simple daily go or no-go signal
- Sleep tracking, which is doing more work than any session
- Weekly running time, a friendlier target than pace for a first build
How to get this plan onto your watch
- Free option, Garmin Coach: covers 5K, 10K and half marathon plans and pushes each workout to the watch. There is nothing for the marathon or ultra distances, and none of it is built around your specific race date.
- Adaptive option, Custom Gains: say your race and date in plain English. It reads your Garmin history, builds the first marathon block around your actual fitness, and pushes each session to the watch, reshuffling the week when you miss days or your recovery drops.
Want this first marathon plan built for you?
Tell the coach your race and your date in plain English. It reads your Garmin, builds the week, and pushes every session to your watch.
Build my first marathon planSet it up on your watch
- Forerunner 55 training plan
- Forerunner 165 training plan
- Forerunner 265 training plan
- Venu 3 training plan
Chasing a time instead? The marathon guide covers pace work and periodisation.
Useful free tools: race time predictor · heart rate zone calculator · overtraining check.
FAQ
How long should I train for my first marathon?
Twenty to twenty-four weeks is realistic if you are building from a modest base. The shorter plans you see assume you already run four or five times a week comfortably.
Should I have a time goal for my first marathon?
No. Finish it, learn how your body handles the distance, and set a time goal for the second one with real data behind it.
How many days a week should I run for a first marathon?
Four is plenty. More running is not what a first-timer needs. Consistency across months is, and four days is far easier to keep doing.
Is it okay to walk during my first marathon?
Completely. Planned walk breaks, especially through aid stations, are a sound strategy and not a failure. Many first-timers finish faster with them than without.