How long does an optimal marathon race training plan last?

What is the recommended duration of a good marathon race training plan based on your profile, whether you are a beginner in running or a regular runner? We explain everything to you in this article.

First, let's quickly dispel a misconception. There is no marathon race training plan duration that is valid for all runners and would be set in stone. The duration of a marathon preparation must be adapted to your runner profile and your goals. The process will necessarily be much slower for a beginner who first wants to be able to finish a marathon. But it can be just as long, if not longer, for professional athletes who want to perform at the maximum of their abilities. Keep in mind that a long preparation will often be beneficial, regardless of your starting level.

You are used to run regularly, at least 2 to 3 times a week. Are you able to handle long runs of 1 hour to 1 hour 30 minutes without much difficulty? Then the traditional 12-week marathon plans may potentially suit your runner profile. Provided you can handle the intensity well, this duration does not allow for as complete a progression as a long prep. If you are more of a novice in the discipline, we recommend extending your prep by a few weeks and opting for 16-week training plans or 20 weeks, for example. 

Once the duration of your plan is determined, subtract the number of weeks from your marathon date and you will know the optimal period to start your prep! 

Indeed, you don't embark on this type of marathon preparation starting from zero, but having already run a good volume at low intensity – the famous base endurance. And for that, you need to plan some time. Ideally, you will have introduced some intensity sessions to develop your speed qualities. Then, you will be ready to handle your marathon preparation under the best conditions.

Marathon plans are structured in blocks of several weeks followed by a more relaxed week, called an assimilation week. In a 12-week plan, we are used to having the most intense week of the prep in week 9 of the plan. It is punctuated by a test workout or a preparatory competition placed three weeks before your marathon. Then, we will gradually reduce the weekly volume. This is called the Tapering phase which will allow you to reach your peak fitness on race day. 

Your training program will therefore include a variety of workouts such as MAS sessions, marathon tempo runs, or endurance workouts... 

In general, runners prepare between 16 and 20 weeks on average to feel ready to embark on the marathon distance. What matters is that the plan allows you to improve your physical condition (cardio and muscle) and prepare your mind for this effort. 

All else being equal and for the same goal, the duration of a training plan obviously depends on your running experience: frequency, volume, and distances already covered. The volume of work that you can allocate to your training plan will inevitably influence the duration of your training plan. The goal is to arrive at the race as sharp as possible. 

This type of very short plan is intended for experienced runners with already intense general training. This duration is generally not optimal. For the preparation of a first marathon, we strongly advise against going below this duration of 12 weeks.

On the contrary, a training schedule spread over 16 weeks or more will offer better progression and allow you to cover a wider range of intensities. This is what we recommend at Campus.

You have never worn a pair of sneakers, or only once or twice a year, and you want to take on the marathon challenge. Rest assured, it is entirely possible… provided you take the time to properly prepare your body and mind to sustain the marathon pace for several hours. In your case, the primary goal is not time-oriented.

As a beginner, you must go gradually. Your priority is to avoid getting injured, as this is the main obstacle to progress. To minimize the risk of injury, you must avoid the "too fast, too hard" approach. Most injuries are due to a rapid increase in training volume and/or intensity. An increase in weekly mileage of about 10% is ideal. Don't forget: rest phases are inseparable from progress.

This multi-month process allows your body to adapt to these new constraints, which relates to mechanical stress, and to strengthen gradually. This timeframe offers the advantage of gradually increasing your number of weekly workouts and scheduling some preparatory competitions. For all these reasons, we can recommend a 6-month preparation time for the beginner.   

It's not mandatory, but preparatory competitions are of real interest during marathon preparation. However, make sure to schedule them at a distance from the marathon and approach them in the right way.

The number one benefit of a preparatory competition is to put yourself in the conditions you will find on marathon day. You will be able to establish your pre-race routine, test your equipment, your running clothes, as well as your race-day nutrition. It's a good way to reassure yourself before race day.

A 10 km or a half marathon will have their place in your marathon plan, provided they are scheduled well before the marathon date and run at the right pace. A half marathon run at full speed during the tapering period is highly discouraged, as it would jeopardize your chances of performing well in the marathon. However, you can approach this half marathon as a major dress rehearsal and run it at marathon tempo for a few kilometers/miles of the 21.1 km/13,1094 miles, even performing your test workout proposed by your Campus plan, but no more.
No matter where you are on your journey, choosing the right marathon race training plan makes all the difference. A well-structured plan means not only steady mileage but also well-timed long run sessions that build your endurance without pushing you into injury. A good marathon training plan help you balance volume, recovery, and intensity, allowing you to reach race day confident and prepared.
Whether you opt for a 12-week build or a more gradual 16- to 20-week preparation, remember: consistent long runs are your anchor. Stick to your training plan, respect the buildup, and the long run becomes more than a workout—it becomes a stepping stone to your best finish time.