London 100
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London 100 : event overview
London 100 is an urban ultramarathon staged from an indoor Run HQ in central London. The event date is Saturday 12 June 2027 and entries open on Friday 26 June 2026. The organisers note that entries for the 2026 edition are closed.
The event offers three challenge distances:
- 100km ultramarathon
- 50km ultramarathon
- 25km Central London run
Four 25km route sections run north, south, east and west of the capital. The full route is described as taking in more than 100 London landmarks and includes sections on hidden trails and well known sights.
Route checkpoints are positioned at the start and the middle of each 25km section. Checkpoints are stock with water, snacks and fruit. The maximum time permitted to complete the 100km is 17 hours. Finishers receive a London 100 medal and finishers in the Top 100 are recorded on the event list.
The organisers describe the event as an urban-ultra designed for accessibility and inclusivity, with Central London chosen to make arrival and departure easier for competitors and supporters. The event works with partner charities and offers charity entries at half price. Volunteers support event delivery and the organisers acknowledge their contribution. Visit the organization's website for the most recent information.
