When Should You Start Training for a Spring Marathon in 2027?

Most runners should start a dedicated spring marathon plan 16 to 20 weeks before race day, which for the London Marathon on 24 and 25 April 2027 means starting between early December and early January. If you are newer to running, use the weeks between now and then to build a base of easy running and strength so that day one of your plan feels comfortable, not like a shock.

With the autumn race season winding down, spring suddenly feels close. This guide gives you a countdown for the main spring 2027 marathons UK runners enter, tells you how many weeks you really need for your experience, and shows you how to use the gap before your plan starts, including Christmas and the worst of the British winter.

When does each spring 2027 marathon plan need to start?

Find your race below, then pick the column that matches the plan length you need (the next section helps you choose). Each start date is a Monday, with race week as the final week of the plan.

Race dates checked against each organiser's website at the time of writing. The Brighton Marathon Weekend runs on 3 and 4 April 2027, with the marathon listed for the Sunday. Boston is on a Monday, so its plan starts match Manchester and race day falls the day after the final Sunday. Dates can change, so check the organiser's site before you book travel. Edge is not affiliated with any of these races or their organisers.

London is the one most people ask about. For the first and only time, the organisers are spreading it across two days to welcome 100,000 runners, so check your entry for which day you are running. If London is your race, our London Marathon 2027 training plan walks through the weeks in detail.

How many weeks do you need for your experience?

There is no single right answer, but most plans fall between 12 and 20 weeks. The less running you have in your legs today, the longer the runway you want. Here is a simple way to choose.

If you are brand new to running, a spring 2027 marathon is possible for some people, but it is a big ask in around 28 weeks. A fairer test is to start run-walking now and see where you are in December. If you can run for 45 to 60 minutes at an easy pace by then, a 20-week plan is realistic. If not, a later race such as Edinburgh on 30 May buys you extra weeks, and that is a smart choice, not a failure.

Experienced runners can get away with 12 weeks, but only if they arrive with a solid base. Twelve weeks from a standing start is how niggles happen.

What should you do between now and the start of your plan?

For most runners, there are somewhere between 8 and 16 weeks between today and day one of their plan. This is your base phase, and it is the part most people skip. Done well, it makes the marathon block feel like the next step rather than a cliff.

• Run easy, and often. Aim for three or four runs a week at a pace where you could chat in full sentences. Easy running builds your engine without wearing you out.
• Build slowly. Add a little time each week, then hold or drop back every third or fourth week. A common rule of thumb is to raise your weekly running by no more than about 10% at a time.
• Grow one longer run. Let your weekend run creep up towards 60 to 75 minutes before your plan starts. That is enough. The long runs will come later.
• Add two short strength sessions. Squats, lunges, step-ups, calf raises, glute bridges and planks, 20 to 30 minutes each. Strong legs and hips help you handle the extra miles later on.
• Do one benchmark. A timed 5K, such as a local parkrun, gives you a starting point to set sensible paces for the plan.

Our guide to base building for runners includes a 6-week base plan you can drop straight into this gap.

How ready should you be on day one of the plan?

A good marker for a first-timer is being able to run three times a week and complete an easy run of 8 to 10km without needing days to recover. If you are there, you can start a 16 or 20-week plan with confidence. If week one of your plan asks for more than you are currently doing, start the plan a little later or repeat the base phase for another fortnight. Starting slightly behind is far easier to fix than starting injured.

How do you plan around Christmas and New Year?

Look at the countdown table again. For a 20-week London plan or a 16-week Brighton plan, Christmas lands in the first few weeks. For a 16-week London plan, it falls just before you start. Either way, the festive fortnight is coming, so plan for it now.

• Make it a lighter week on purpose. Shorter, easy runs and one strength session. A planned easy week is part of good training.
• Move the long run. Christmas Eve morning or Boxing Day often work better than the big day itself.
• Do not chase missed sessions. If you lose a few runs, pick the plan up where it is in January. Cramming them in later is a classic recipe for an injury.
• Travelling? A 20-minute run or a short bodyweight HIIT session in a spare room keeps the habit alive.

What about winter weather and dark evenings?

Every spring marathon plan in the UK is built in winter, so the cold, wet and dark are part of the deal. The UK clocks go back on Sunday 25 October, so most weekday runs after work will be in the dark from then on.

• Save your long run for weekend daylight, and keep weekday runs on lit, familiar routes.
• Wear something bright or reflective, and layers you can take off as you warm up.
• On icy days, swap the run for a treadmill session, a bike or an indoor strength day. One lost run will not decide your race, but a fall on ice could.
• Keep two or three indoor backup sessions ready so bad weather means a swap, not a skipped day.

Is it ever too late to start?

Not yet. On 6 October 2026, every race in our table is at least 21 weeks away, so even a cautious 20-week plan fits for all of them. Tokyo is the tight one, with a 20-week plan starting on Monday 19 October. If you leave it until February, you are into 12-week territory for London, which suits experienced runners only. Whatever you choose, it helps to know the most common spring marathon training mistakes before the peak weeks arrive.

How can Edge help you get to the start line?

Most marathon plans only cover running, which leaves you to fit strength and mobility in yourself. Edge treats running, strength, HIIT and mobility as one plan, so your base phase, your strength sessions and your marathon block sit together in the same week. Tell Edge your race and when you want to start, and your fully personalised plan is ready within 24 hours. You can message a real coach anytime, whether that is a question about paces or what to do when snow wipes out a long run.

Edge is free to download, and Edge Pro, from £19.99 a month with a 7-day free trial, adds the personalised plan and coach. It syncs with Strava, Garmin, Apple Health and Coros, and 20,000+ members already train with it.

This article is general guidance, not medical advice. If you are new to exercise, returning from injury, pregnant, or managing a health condition, speak to your GP before starting, and see a physio for any niggle that does not settle.