Course
An urban ultra built from four 25km routes radiating north, south, east and west from a single central London headquarters, so every option starts and finishes in the same place. The full 100km links all four; runners can also take one 25km leg or a 50km pairing. The route passes more than 100 London landmarks along streets, parks and hidden city paths. Checkpoints with water, snacks and fruit at the start and midpoint of each 25km section.
Key dates
- !RegistrationOpen now
- ★Race daySat 12 Jun 2027
About
The London 100K is Central London's premier urban ultra marathon, challenging runners with a 100km course through the heart of the historic city. This unique event offers an unparalleled opportunity to experience the iconic landmarks and vibrant atmosphere of the United Kingdom's capital while pushing the limits of endurance.
Save London 100K to your season and RunCalendar reminds you the morning entries open and before they close. Free on iPhone, no account needed.
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South Downs Way 100
One hundred miles of chalk ridgeline to Eastbourne
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Cotswold Challenge
Ultra along the scenic Cotswold Way through rolling hills
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Race for Life Watford
Along the Grand Union Canal through Cassiobury Park
A confirmed date shows its day; a provisional one shows only its month, because we won't claim a day we don't have. This page is rebuilt every night from the RunCalendar catalogue.