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London 100km Ultramarathon
This is not your typical ultra. Forget muddy fields and remote, windswept fells. The London 100k is Central London's one and only 100km ultra marathon, a gruelling, exhilarating urban adventure that takes you on a tour of the capital like no other.
This is your chance to see over 100 of London's most iconic landmarks and discover its hidden green trails, all in one unforgettable run.
One of the best things about an urban-ultra? It’s accessible. The race starts and finishes from a superb indoor Run HQ right in the city centre.
That means no faffing with long drives to the middle of nowhere, no expensive race-day accommodation, and it's an absolute dream for your support crew and spectators, who can easily hop on the tube to cheer you on at multiple points.
Course
This 100km course is ingeniously designed. From the central Run HQ, you will tackle four distinct 25km routes, exploring the north, south, east, and west of the capital.
Each loop takes you on a different journey, from world-famous sights to the quiet, hidden trails and parks you never knew existed. You'll return to the HQ after each 25km loop, giving you the perfect chance to refuel, regroup, and see your crew before heading out on the next leg of your adventure.
Well-stocked checkpoints are positioned at the start and middle of each 25km loop, so you're never far from energy and support. Expect water, snacks, fruit, and plenty of encouragement.
So are you ready to take on a 100km tour of London? Visit the official race website for full details and registration info.
