Preparing for the 2027 London Marathon: the most popular major
The London Marathon is run at the end of April, from Greenwich to the Mall, in front of the densest crowds on the calendar. A course that descends then flattens, it is prepared like a fast marathon, with a preparation window that overlaps Paris. Here is the plan set on your Garmin data.
Last updated: 2026-09-19
Downhill at the start, flat afterwards
The first three kilometres from Greenwich descend clearly, then the course stays flat along the Thames, with Tower Bridge at the 20th and the long loop around the Isle of Dogs. The cobbles around the Tower of London are the only rough patch.
The crowd is continuous over 42 km: a huge mental help, and a trap for pacing. The plan insists on a cautious start despite the descent.
A late-winter preparation
Late April: a 16-week plan from early January, or 12 weeks from early February. The peak load falls in March, as temperatures soften: the ideal window.
The AI coach reads your actual sessions every week on Garmin and builds the long run from 90 minutes to 2 h 45 without ever exceeding 15% extra volume from one week to the next.
Pacing and managing the crowd
Instruction: first three kilometres at target pace plus 10 seconds despite the descent, target pace afterwards. At Tower Bridge the noise makes everyone speed up: look at the watch, not the crowd.
- January: volume, long run up to 2 h.
- February-March: marathon-pace blocks, 2 h 45 long runs.
- April: taper, last long run three weeks out.
The plan's "Race" session carries the pace range per segment. Schedule it on the watch the day before and let it alert you.
Frequently asked questions
When is the 2027 London Marathon?
Late April, traditionally on a Sunday. Check the official date before entering it in your plan.
How do you get a bib?
Through the ballot, a qualifying time, a tour operator or a charity place. The ballot opens right after the previous edition.
Is London a fast course?
Yes: downhill then flat, sheltered, temperate. World records have fallen there. The only trap is a pace carried away by the crowd.
Ready to prepare for your marathon?
Pick your race date and weekly session count: your AI coach builds the plan and pushes it to your Garmin.
Start the marathon plan