London 100

London 100

London 100 is an urban ultramarathon that starts and finishes in central London. It is presented as Central London's only ultramarathon and is described as a route that showcases more than 100 of the capital's landmarks and sights.

The route runs through and around central London using a mix of surfaces including trails, towpaths, pavements and footpaths. This is an open road event rather than a closed road race; participants will need to cross roads at pedestrian crossings and take care with other pavement users.

Distance options include:

• 100 km - ultramarathon distance
• 50 km - ultramarathon distance
• 25 km - East and West route options

The event applies age and completion rules: all entrants must be 18 or older on race day. Time limits are set for each distance and are calculated from estimated completion times provided at registration; the published maximum times include up to 17 hours for the 100 km course, 10 hours for the 50 km course and 5 hours for the 25 km course.

Finishers receive a commemorative medal and the event notes community support along the route. The organiser stages the event within the urban environment and on shared-use paths. Visit the organization's website for the most recent information.