The London Marathon will take place over two days as a one-off occurrence in 2027 with men’s, women’s and elite events spread across the weekend.

The 2026 edition was the site of multiple milestones, including Sabastian Sawe’s world record one hour, 59 minutes and 30 seconds in a race where both the Kenyan and Yomif Kejelcha of Ethiopia broke the two-hour barrier for the first time in history.

It also attracted a record 59,830 finishers, and more will have a chance to run the same course next year with 100,000 participants welcomed across the weekend of April 24 and 25, 2027.

London mayor Sadiq Khan said: “London is the sporting capital of the world and I am delighted that, for one year only in 2027, the world famous TCS London Marathon will expand into a two-day event.

“This unique, one-off double will allow a record 100,000 participants to take part across the two days – creating the largest fundraising moment in UK sporting history and supporting the work of so many incredible charities.

“The London Marathon showcases the very best of our capital and we will continue working closely with London Marathon Events and our partners to ensure appropriate measures are in place for the entire weekend as we build a better, more prosperous London for everyone.”

Elite women, elite female para-athletes, championship and ‘good for age’ women will compete on one day, and their male equivalents on the other, with the exact details to be confirmed.

A record 1.33 million people have already applied for the 2027 edition, following more than £90 million ($169.48 million) raised for charity by participants in 2026 – a figure organizers hope will be much higher as a result of expanded capacity across two days.

Those whose ballots are successfully drawn in July will be able to participate in person on Saturday or Sunday, but not both.

Organisers have also set aside two guaranteed entries for every school in the capital for teachers or staff, and extra guaranteed entries have also been allocated to every London borough along the route.

London Marathon CEO Hugh Brasher estimates that more than £150 million can be raised for charities and good causes through the expanded edition, while he estimated the UK will benefit from £400 million in social and economic benefit.

He added: “The 2027 TCS London Marathon Double is our most ambitious evolution to date – a once-in-a-generation one-time-only reimagining of what a marathon and city-wide celebration of activity can be.”