The 2027 London Marathon will expand from a single day to two days, creating nearly 40,000 additional race spots. Organizers announced the change to accommodate growing demand for the world's largest mass-participation marathon, which currently attracts over 40,000 runners annually.
The two-day format splits the race across consecutive days, each hosting roughly 20,000 runners. This expansion addresses the marathon's persistent lottery system, where hundreds of thousands of applicants compete for limited entries each year. The ballot announcement for 2027 spots comes in July.
Race director Hugh Brasher stated the expansion reflects the event's cultural significance and the public's enthusiasm for marathon running in Britain. The two-day structure maintains the iconic London course while distributing participant volume more evenly.
Runners selected through the ballot system will discover their placement in July. The lottery system remains unchanged in process, though the expanded field significantly improves odds for applicants. Previously, acceptance rates hovered around 10 percent for ballot entries.
The announcement comes as marathons worldwide grapple with capacity constraints. London's growth mirrors trends across major races, including Boston and New York, where demand consistently exceeds available spots. The expansion represents a practical solution that preserves the race's character while welcoming more participants.
Organizers confirmed that all other race details, including the route and support infrastructure, will accommodate the two-day format. The expanded London Marathon reflects broader shifts in endurance sports participation, with marathon entries climbing across Europe and North America over the past decade.
For 2025 and 2026, the marathon maintains its traditional single-day structure, giving organizers time to finalize logistics for the 2027 expansion. The decision balances accessibility with operational feasibility, allowing more runners to experience one of running's most prestigious events.