TCS London Marathon

TCS London Marathon is one of the few races that feels huge in every direction at once: elite race, charity machine, mass-participation event, and national spectacle. The ballot is hard, charity entry is central to the event's identity, and the whole weekend carries more collective energy than most marathons can manufacture.

The 2027 edition is different. For one year only, London expands into the TCS London Marathon Double, running on Saturday 24 and Sunday 25 April with a record 100,000 participants split across the two days on the same Greenwich to Westminster route. Runners are assigned a day rather than picking one, so wait for your confirmation before booking travel or accommodation. The format reverts to a single Sunday afterward.

The route is flat enough to run well, but the experience matters as much as the profile. London gives you long city-center miles, dense crowd support, and signature moments at Tower Bridge before the finish on The Mall. It is less of a pure time-trial setup than Berlin or Chicago, but it rarely feels empty.

Late April in London is often cool and workable, though dry air, unexpected sun, or a stiff breeze can make the second half harder than the pace bands suggest. The course gives you crowd energy almost everywhere, but it does not hide bad pacing.