London is the marathon of crowds. The organisers call it the most popular marathon on the planet, and in 2027 it gets bigger still: for one year only, the race runs over two days, with around 100,000 runners on the same course from Greenwich to The Mall.
That format changes your preparation more than you might think. You do not pick your day, the Saturday has a hard finish time, and the spring date means your whole build-up happens in winter. This page turns those facts into training decisions.
TL;DR: Plan a winter build-up of 16 to 18 weeks toward 24 or 25 April 2027, and train for the day you were given, since it cannot be changed. If you run on Saturday and expect to need close to 7 hours 45 minutes, the finish closes at 17:30. London is close to flat, so the challenge is pacing through the crowds: three start lines merge before mile 3, and Tower Bridge pulls everyone faster just before halfway. Practise with Lucozade Sport if you plan to use the course drinks.
What makes London 2027 different?
- Two days, one course. Saturday 24 and Sunday 25 April 2027 use the same route. You run on one day only, and the day you are assigned is fixed: no swaps, no date changes, not even to run with a friend.
- The Saturday has a clock. The Saturday start is likely to be around 09:00, and the finish on The Mall closes at 17:30. That gives you at most 7 hours 45 minutes. The organisers ask runners who expect to need longer not to take up a Saturday place.
- The elite and championship races are split by sex. Men run their Championship and Good For Age races on Saturday, women on Sunday. If you entered through Good For Age, your day follows from that.
When should you start training?
The race is in late April, so the specific block runs through January, February and March. That is the hardest part of the year to train in, and it shapes three choices.
- Build the base in autumn. Use October to December for easy volume and strength work, so you start the specific block fit instead of starting from scratch in January.
- Start the specific block in early January. Sixteen weeks before 24 April is the first week of January. Long runs, goal-pace work and fuel practice happen from there.
- Plan around the weather, not against it. Have an indoor or treadmill option for the sessions that matter most, so a week of ice or storms does not cost you a key long run.
Taper over the last two to three weeks. Volume drops, intensity stays.
How do you pace London?
The course has 246 feet of elevation gain, which is close to flat. The pacing problem in London is the crowd, not the hills.
- Expect a slow first three miles. The race starts on three separate lines, and the runners from all three meet for the first time just before mile 3 in Woolwich. Accept the congestion and do not spend energy weaving.
- Hold back at Tower Bridge. Just before halfway you cross Tower Bridge, and the organisers describe the noise there as a wall that pushes you across the river. Enjoy it, and check your pace on the other side.
- Save something for the last five miles. The final stretch runs along The Highway, Tower Hill and Victoria Embankment, past Parliament Square and Buckingham Palace to the finish on The Mall. The crowds there are huge, and they help most if you still have legs.
- Use the pacers. Pacers run from 3:00 to 7:30. Find yours at the start and stay with the group until the last miles.
How do you plan your fuel?
The drinks stations serve water, Lucozade Sport and Lucozade Sport Energy Gels. The official overview does not list the gel points per mile, so check the participant guide when it comes out.
- Practise with Lucozade Sport if you will use it. A drink your stomach has never met is a risk on race day. If you prefer your own products, carry them.
- Carry your own gels anyway. Whatever the course provides, the safest plan is the one you rehearsed on every long run, with your own gels at your own intervals.
What does race weekend look like?
You receive your start wave time by email about three weeks before the race. The Running Show at ExCeL London is open from Tuesday 20 to Saturday 24 April 2027, so on the Saturday it runs while day one of the race is on. If you run on Saturday and want to visit, go earlier in the week.
Plan your travel around your assigned day, and book your hotel once you know it, since the day cannot be changed afterwards.
How does a coach help for a race like London?
A good plan gets you to the start line. A coach adjusts it on the way: the week of snow in February, the long run you missed, the goal time that turns out too ambitious in March. For London, a coach also helps with the decisions on this page: how to train through winter, how to pace a crowded start, and how to fuel when you do not yet know the gel points.
On Coachbox you can tell us exactly that. Choose “Help me find a coach” when you sign up, give the London Marathon as your goal, and we introduce you to a coach who fits. Or read how to find a running coach who fits you first.
Every fact on this page has a source
Dates, entry routes, cut-off times and the course come from the organiser’s own pages, linked in the facts at the top. We checked them on the date shown there. The 2027 format is new and details are still being added; if you spot something that no longer holds, let us know and we will update it.