12 Week Marathon Training Plan

Our 12 week marathon training plan is designed for runners looking to get ready to run 26.2 miles in just 3 months!

The 12 week marathon training schedule is best suited to runners with at least 6 months of running under their belts; you should be able to run 10km continuously before you begin.

Think of this as more of an intermediate or even advanced plan than a beginner’s plan.

It ramps up the mileage and training quickly to suit your tight training schedule.

Scroll down to grab a copy of the free marathon training plan – available in both PDF and Google Sheets and in km or miles, so you can customize it!

Otherwise, let me walk you through some of the finer points of training for a marathon in 12 weeks.

Can You Train For a Marathon in 12 Weeks?

Yes – 12 weeks is sufficient to get marathon-ready.

The main pre-requisite is that you should already have a foundation of running experience.

If you can run 10k without stopping right now, you’re in good shape to begin the 12 week marathon training plan.

The plan includes quite a rapid increase in weekly mileage, so it’s important to follow the plan closely, but also know when to take breaks – in other words, listen to your body.

The 12 week marathon training plan includes a 3 week taper period – meaning that your training actually peaks after 9 weeks, then the final 3 weeks are a gradual reduction in training volume to ensure you’re rested and prepped for your 26.2 mile race day.

A lady running over rocks in front of a sunset or sunrise

20 Week Marathon Training Plan: Essential Info

Who Is It For?:

Runners who have established an initial running base, or have an existing good fitness level.   You should be able to run 10km without stopping.

You don’t need to be an advanced, or very experienced runner, to follow this free plan – but you do need to have built up some running experience.

The 12 week marathon training plan’s weekly mileage builds fairly quickly, so it’s important that your body is already well-adapted to running before starting.

Not sure this is the plan for you? – Check out our other marathon training plans.

How Long?: 

3 months // 12 weeks.

This includes 9 weeks of gradually increasing mileage, peaking with a 21 mile long run 3 weeks before your marathon.

The final 3 weeks are your taper period – we gradually reduce training volume over those 3 weeks to ensure that when you get to your start line you are rested, recovered, and well-fuelled.


This 12 week marathon training plan has you working out five days a week – four days of running and a day of cross-training, with two days off.  

I always include one day of cross training in my marathon training plans – for me, cross-training is the secret sauce that makes you less injury-prone, stronger, faster, and boosts your endurance. However, some runners choose to skip the cross training and take an additional rest day.

If that’s you, no worries!

A man running on a running track

Training Breakdown: What Will Your Weekly Schedule Consist Of?

Given the relatively short training time, the important thing to focus on is building your endurance rather than speed.   

Attempting to improve both endurance and speed in this short window is likely to stress your system too much, and will quickly lead to injury, illness, fatigue, burn-out, and exhaustion.

That’s why a balanced marathon training plan is so important; you need a plan which adds the requisite mileage while pushing the limits of your endurance but allowing time for recovery too.

Regular Training Runs

There are 3 regular training runs per week in the 12 week marathon training program. 

Your regular training runs should be performed at a sustainable pace – unless you have a specific pace target, aim to run at a conversational pace throughout. In other words, maintain a pace at which you could comfortably hold a conversation.

These runs are all about adding to your weekly mileage and honing your running economy and form.

If you have a specific pace target or finishing time goal, you can make use of our Marathon Pace Calculator to plan your race day pacing.

Long Slow Runs

For your Long Runs, the aim is simply to get your body used to running for a long time – so take them easy, don’t push yourself.  

These long runs are all about increasing your endurance, specifically;

  • Improves your muscles’ ability to perform after running for hours (time to fatigue)
  • Improves your cardiovascular system’s efficiency while running
  • Boosts your mitochondria (i.e. your body’s fuel-burning ability), so your body is better equipped to turn energy stores into muscle power on marathon day
  • Mental and logistical preparation for running long distances!

If necessary, take occasional walking breaks – just try to maintain a good rhythm and not stop completely

Cross Training

Cross-training is a great way to keep fit and ensure your marathon training does not negatively impact other parts of your body.  

Cross-training improves your cardiovascular health and strengthens some of the muscles weakened through running, thereby reducing your chance of injury.

Recommended cross-training exercises include bodyweight exercises, light gym work, swimming, yoga, pilates, and cycling!

Check out our cross-training guide for runners to learn more.

Just avoid high impact of very intense workouts – I recommend giving activities like spin classes and CrossFit a rest when following the 12 week marathon training plan, otherwise you increase the risk of injury and burnout.

Run Intensity and Rest Days

When it comes to run training intensity, don’t overdo things – given you only have 12 weeks to prepare, speed is secondary to getting the miles in.  

If your body is worn out, allow it some rest.  

Don’t be too worried about skipping a training day during the 12 week marathon training plan – but if at all possible, don’t miss your weekly long runs.

Get The Complete Guide

My guidebook, Marathon in 3 Months, is available now for instant download. It maps out the complete training strategy and rationale behind the 12 week marathon training program supplied. It walks you through your week-by-week training and preparation to get you to the finish line in under four hours. 

Download The 12-Week Marathon Training Plan For Free:

12 Week Marathon Training Plan - printable

Download The Training Plan Here

Enter your email, and I’ll send you this free training plan now, in PDF and Google Sheets formats (completely customizable), in both miles and kilometers.  

After entering your email, you’ll be prompted to create an account on the Grow platform we use to control access to the plans. It’s completely free – make sure to complete the process to gain access to the plan!

Previous visitor or not seeing where to sign up?

Head over to our marathon training plan database for full access to all plans.

download the free training plan

Check Out The Premium Version of The 12 Week Marathon Training Plan . . .

We’ve teamed with TrainingPeaks to offer a premium version of the 12 Week Marathon Training Plan:

Access the plan via the TrainingPeaks website and app, track your workouts in real-time against the plan, and get performance data analysis on your progress.

Check out the premium 12 week marathon training plan here!

12 Week Marathon Training Plan 1
trainingpeaks training plan
12 Week Marathon Training Plan 2
12 Week Marathon Training Plan 3

Proven Training Plans by a UESCA-Certified Running Coach 

Every one of our training plans has been developed by Thomas Watson, a UESCA-certified running coach.

Thomas is also a podium-finishing ultra-marathon runner and has dozens of marathons under his belt.

Each training plan has been road-tested by hundreds of runners, refined and improved, and is free to download and customize to suit your needs!

Other Suggested Marathon Training Plans

Beginner + Novice Training Plans

Intermediate Training Plans

Advanced Marathon Training Plans