The London Marathon is exploring a significant expansion that could see participation numbers double to over 100,000 runners through a pioneering two-day format beginning in 2027.
According to Guardian reports, organizers are developing plans for what's being called the Double London Marathon, which would fundamentally reshape one of the world's most prestigious mass-participation running events.
The proposed structure would distribute 50,000 amateur participants across each day—April 24 and 25—with discussions ongoing about potentially scheduling elite competition across the weekend as well.
The expansion carries substantial implications for charitable fundraising. Last year's event saw 56,540 finishers generate £87.3m in donations, suggesting a doubled field could potentially raise upwards of £130m. Demand remains extraordinary, with over 1 million entries submitted for the 2026 edition scheduled for April 26.
While the London and New York marathons have historically competed for the title of largest amateur field, a 100,000-runner London event—even across two days—would establish a benchmark unlikely to be matched by its American counterpart.
Stakeholder Coordination Underway
Hugh Brasher, chief executive of London Marathon Events, told the Guardian: "The TCS London Marathon is the world's most popular marathon, and we are always exploring innovative ways to enable more people to take part and to deliver positive benefits for London.
"This work is carried out in close collaboration with our partners and stakeholders, whose support is essential in staging this incredible event in the heart of the capital each year."
A spokesperson for the Mayor of London emphasized the city's commitment to major sporting events: "London is the sporting capital of the world and the Mayor looks forward to working with London Marathon and partners to consider if it might be possible to host an event that will run across two days next year."
The 2025 elite races showcased East African dominance, with Kenya's Sabastian Sawe claiming victory in the men's division ahead of compatriot Alexander Mutiso Munyao and Uganda's Jacob Kiplimo.
Ethiopia's Tigst Assefa secured the women's title on The Mall, finishing ahead of Kenya's Joyciline Jepkosgei and the Netherlands' Sifan Hassan, who has since withdrawn from the 2026 competition.