London 100 is Saturday 12 June 2027. The event will run from 7am to midnight.

Start times vary, based on distance and your estimated completion time. Slower estimated completion times will be given earlier start times.

Last date for entries is Sunday 6th June 2027 at 22:00 (if not sold out before)

London 100 includes the following distances:

London 100km ultramarathon

London 50km ultramarathon

London 25k (EAST) 7-7.30am starts

London 25km (WEST) 7-7.30pm starts

Yes, we are being timed by our partners Krono Sports - there will be a link you can share with friends and family they can see the time you reach the RunHQ each time.

London 100 has launched. Registration is here.

Entries to London 100 close at 22:00 Sunday 6 June 2027, if not sold out before.

If you're unable to join us in 2027, but you're keen to hear about when we launch future events, we recommend you registering your interest here.

For central London's only ultramarathon, we wanted to give you the best support, run past the best sights and to see the amazing variety that Central London provides.

We have planned our route in 4 sections (East, North, South, West). Each of these sections is 25km long. The London 100 100km participants will complete all 4 sections. The London 100 50km participants will complete 2 sections (North and South). The London 100 25km participants will complete 1 section (East or West).

The routes are largely out and back. The reason for this is to ensure ease of navigation, but it also gives you a great opportunity to hi-5 or support your fellow runners as you see them along the route.

London 100 is an urban ultra, and as such we are an open-road event, not a closed road event. Participants will need to safely navigate some road crossings (largely at pedestrian crossings) and yield to other pavement users. There will be times when you're running in wide open spaces in parks etc and other times when you're running on some busy pavements. Either way, this is all part of the beauty and variety that a city like London delivers.

The sights you see will be epic and you are sure to discover some new areas of the capital that you didn't know existed. Enjoy the ride!

We have a strict NO PACER rule. We are an urban event where the nature of pavement and street running means that each runner needs to focus on their own running and not influenced by a pacer.

We do allow a buddy to support you in the final 25km leg of the 100km distance.

Pacers/buddies are not permitted in the 50km and 25km challenges.

We have a sweep team who will follow the final runner, and take down all event signage as they go.

There is no sweep vehicle, but if you have a payment card with you, and you need to reture from the event, then you can travel on public transport to your preferred destination. Please note that all retirements need to be informed to Event Control, and you may need to return to RunHQ for your bag. Medical assistance reached through Event Control.

The London 100km will have starts from 7am. The London 50km will have starts from 9am. The London 25km will have two start times, based on which route you choose (East 7-7.30am starts, West 7-7.30pm starts).

Starts are in small groups to avoid congestion. The arrangement of the start times will be arranged on estimated completion time (slower estimated completion times starting earlier). Following your entry, you can amend your estimated completion time by logging into Race Nation and adjust your time any time up to 10pm Sunday 6 June 2027.

As a guide, the start times will be as follows:

London 100 - 100km start times between 07:00 and 07:30

London 100 - 50km start times between 09:00 and 09:30

London 100 - 25km EAST start times between 07:00 and 07:30

London 100 - 25km WEST start times between 19:00 and 19:30

The actual individual start wave times will be published closer to the event date. However, your start times will not vary from the broad start times listed above.

See other FAQ on help to log back in

Run HQ is our Central London base for London 100. It is a huge indoor space in Central London just around the corner from Victoria Station, Buckingham Palace etc. Our RunHQ is the start, finish and main checkpoint between the routes.

Run HQ is the Queen Mother Sport Centre, 223 Vauxhall Bridge Road, Pimlico, SW1V 1EL. What3Words location: ///couch.hooked.gender

Run HQ acts as our start, finish and the interchange point between each of the 4 sections of the run (East, North, South, West). It will be dry, warm, well stocked and a perfect place to leave some of your kit, so you're not carrying every item with you on your runs.

You could even get your head down for a quick nap if you wanted.

Run HQ has other benefits: it's close to major transport for getting to and from the event and is easy to access for spectators and your supporters. From one vantage point your supporters could see you up to 8 times!

We will have the following at RunHQ:

- Start and Finish line

- Toilets and showers

- Water and Checkpoint food

- Bag drop

- Some tents, in case you need a quick lie down

- L100 Core Team at all Times

- Volunteers assigned to get your Bag and assist you with what might life easier - Masseurs tbc (Recovery Zone)

- Specialised Medic Team

- L100 Brand Partners - they may have runner based items that might be helpful if you have any kit failure

- RunHQ closes at 00:00 (midnight)

There is no mandatory kit list, but we do strongly recommend the following:

- fully charged mobile phone (with Event Control number saved)

- downloaded route files/Google maps to help you navigate

- What3Words app, to help you pinpoint your exact location to Event Control

- payment card - for any local purchases (as an urban-ultra you will pass many local shops, if you need anything)

A full list of the kit list will be available soon in our Runner's Guide - which will be shared with all entrants prior to the event.

The routes are mainly footpaths/pavements, with some trail. We recommend road shoes.

Vegan Energy Balls Flapjacks Chews Veggie Savoury Pastries Fruit (Full options) NO NUTS (allergies)

Our RunHQ, which entrants in the 100km will pass 5 times has toilets. There are also toilets at some of the Checkpoints and we do pass some publicly accessible toilets. More details will be provided in the Runner Guide.

We will provide a list of the best places on the rouite, as part of the Runner Guide.

Yes, the maximum time permitted is 17 hours for the 100km distance. This will require the entrant to be in the very first wave starting at 07:00, finishing before midnight.

Participants in the 50km have a maximum 10 hours to complete their challenge.

Participants in the 25km have a maximum of 5 hours to complete their challenge.

All participants must be finished by 00:00 (midnight).

On the course will be volunteer runners - they will be liaising with Event Control and positioned in places we believe solo runners might benefit from. At the Checkpoints and RunHQ you can ask if you wish for someone to head out with you for a section.

You can volunteer here.

The London 100 100km run will follow the East - North - South - West.

The London 100 50km will follow North - South routes

The London 100 25km will follow the East route (7-7.30am starts)

The London 100 25km will follow the West route (7-7.30pm starts)

Each intersection (start and end) between the routes will be through our Run HQ at Victoria

Yes, if you've entered and can no longer take part, you are able to cancel your place.

As per the terms and conditions of entry, we unfortunately cannot provide a refund or deferral, but we do have a flexible policy, so here's what is available to you if you did want to cancel:

- Firstly, did you purchase the Refund Protect insurance when you entered? If you did you may be able to make a claim - To see everything protected under the policy please click here.

- Transfer - you can transfer your entry to someone else or to a different distance, if completed before 6 June 2027 (10pm). A transfer can be a transfer to someone else or to a different distance (subject to availability). There is a £5 fee for transfers. Please see next question for help on transferring your place

- If you are unable to transfer, then please email us at info@participationsport.com and you can be entered on to our list to receive a priority entry period and discount to the following year's event. As long as this email is received before 11 June 2027, it will be accepted and you'll be added to our list

Yes, you can transfer your place - either to someone else or to a different distance. Transfers need to be completed before 10pm 6 June 2027. A transfer fee (£5) will apply and be paid by the person entering.

Transfers are only possible if there is capacity remaining in the challenge distance you are transferring to.

Full guidelines for transfers here.

Transferring to a new Entrant

1. To transfer your entry you will need to log into your MyRaceNation account with the email address that you used to sign up to the event

2. If you've never logged in before click Logging in for the first time , enter the email address you registered with, agree to the T&C and click Claim Account

3. When you have successfully logged in, you will need to locate the entry you wish to transfer and click on the Transfer button.

4. Select Transfer to another entrant

5. You will then be asked to enter the email address of the person you wish to transfer to and select Start transfer. This will automatically send an email invite to the new entrant

6. Once the person you're transferring to receives the email, they must click the Start Your Transfer and complete their details. Please note if the event organiser has applied a transfer fee this will need to be paid for by the person accepting the transfer.

7. When they have completed their registration they will automatically be entered in the event and the original entry will be cancelled.

8. Please note no refunds are processed. Payment will need to be arranged between yourself and the new entrant taking over the entry.

To log in to your account, to change details, add merchandise, transfer, change your estimated completion time etc - please follow the steps listed in this link:

https://support.race-nation.com/article/128-how-to-log-into-your-myracenation-account

We welcome all supporters to the event and we recognise what an important role they can play in your challenge.

At RunHQ there will be designated runner area, where no support crew will be allowed. But there will be areas for supporters to gather and assist you.

Elsewhere on the route, supporters are encouraged, as long as they understand that they are not part of the event, so not impede other participants or footpath users and they positively help all participants.

Running buddy's are not permitted, however one buddy per runner is permitted for the 100km on the final leg (West).

Runners are permitted to use headphones, but must ensure the volume is set to a level where they can easily hear the instructions of our marshals and the noise of the traffic and other pavement users.

Simply call Event Control on your mobile phone to confirm a retirement. Or you can retire by informing one of the Event Team at the Checkpoints/RunHQ

Support pages for Refund Protect here: https://support.race-nation.com/collection/195-refund-protect and their t&cs (which are linked in the articles) here: https://www.refundable.me/en

Please be aware that the Refund Protect Insurance is not part of or anything to do with the event organisers, and is offered by the registration platform Race Nation, as an option that you can purchase on entry only.