London Triathlon (London T100 weekend, ExCeL)
London (ExCeL, Royal Victoria Dock), United Kingdom · August · Independent (PTO / T100 festival; formerly Challenge London and AJ Bell London Triathlon)
Why people love it
- Olympic bike on closed roads passes Tower Bridge and the London Eye over 40 km (25 mi)
- Sheltered dock swim, expected 18 to 21 °C (64 to 70 °F), with white caps for nervous swimmers
- Flat 2.5 km (1.6 mi) run loops make for a fast run
- London City Airport is 4 km (2.5 mi) away, with DLR and hotels at ExCeL
- Ability waves make the sprint a sound first-race choice
Watch out for
- Past racers report swim-exit bottlenecks, a huge transition and congested run paths. Leave time to find your bike.
- Not cheap: ExCeL parking is £25 per day and past reviewers called entry overpriced
- A 2023 racer called the bike surface poor. The only hills are ramps and overpasses.
- Poor spectating on the bike. Family sees you best at the swim exit and run.
- The 2026 sprint bike was 17 km (10.6 mi), not 20 km (12.4 mi). Recent racer reports are scarce.
Race
How racers feel about it, how well it is run, and how it treats a first timer. Counts for 30% of the overall score.
Toughness: Moderate
- Racer satisfactionLoved3.6
Reader reports are mixed: 3.7 of 5 in 2017, 3.1 in 2015, upbeat memories in 2014. Nothing recent from racers. · Low confidence
- OrganizationWell run3.6
Well signposted, but swim-exit and transition bottlenecks and a 2015 ambulance stoppage. The 2025 algae scare was cleared by testing. · Low confidence
- First timer friendlyDoable3.3
Olympic has four crowded run loops and a long Westminster bike route, but is still flat and closed. · Low confidence
Course traits, not part of the score
- PR potentialAverage3.3
Closed, flat 40 km (25 mi) bike but crowding and ramps. 2013 median about 3:13. · Low confidence
Swim
Wetsuit odds, water temperature, calm, and the experience of the start. Counts for 16% of the overall score.
- Wetsuit legalAlmost always4.5
Expected water is 18 to 21 °C (64 to 70 °F). The organiser makes wetsuits compulsory at or below 24.9 °C (76.8 °F). · Medium confidence
- Water temperatureComfortable4.1
Expected 18 to 21 °C (64 to 70 °F), about 20 °C (68 °F) in 2025. A 2014 racer found it cold and grey. · Medium confidence
- Calm waterMostly calm4.3
Enclosed dock with no current or swell. Only wash from crowded swims. · Medium confidence
- Swim easeEasy3.5
1.5 km (0.93 mi) single dock lap, with longer exposure to crowding. · Low confidence
- Swim experienceFine3.2
Urban dock with clean water per tests and a lively exit, but a scrappy exit, slow stairs and a wetsuit removal queue. · Low confidence
- Swim supportGood4.0
Ability waves, pulse starts about 2 seconds apart, white caps for nervous swimmers and a marshalled dock. · Medium confidence
Bike
Road surface, closures, scenery and wind. Counts for 18% of the overall score.
- Road surfaceMixed2.8
A 2023 racer called the surface poor. Others describe it as functional and industrial. · Low confidence
- Road closuresMostly closed4.4
Reports and the organiser describe traffic-free, marshalled roads. An ambulance stoppage in 2015 was the one issue. · Medium confidence
- Bike sceneryBeautiful3.8
The Olympic route passes Tower Bridge and the London Eye, about 40 km (25 mi). The sprint stays in plain Docklands. · Medium confidence
- WindSome wind3.4
Buildings shelter the Docklands, the river stretches are more open. No wind data published. · Low confidence
Course traits, not part of the score
- Bike speedFast3.6
Longer route with tunnels and a turnaround, and a poor surface in places. · Low confidence
- Bike flatnessMostly flat4.1
No published climbing. The long Westminster route is flat apart from ramps. · Low confidence
- Bike simplicitySome technical parts3.2
Ramps, tunnels and pedestrian crossings that a 2017 racer found risky. Otherwise mostly straight. · Low confidence
Run
Crowds, aid stations, conditions underfoot and scenery. Counts for 13% of the overall score.
- Crowd supportDecent3.3
Lively swim exit and finish carpet. Run loops are crowded with athletes rather than lined with fans. · Low confidence
- Aid stationsStandard3.3
No specific reports. Assumed standard for a UK mass-participation race. · Low confidence
- Run sceneryPleasant2.8
Functional dock-side loops. Reviewers say they may bore some people. · Medium confidence
- Run conditionsModerate3.3
Four loops through a crowded course. · Low confidence
Course traits, not part of the score
- Run flatnessFlat4.8
Flat 10 km (6.2 mi) over four 2.5 km (1.6 mi) loops. · High confidence
Conditions
Air temperature, how predictable the weather is, setting, and spectating. Counts for 13% of the overall score.
- Air temperaturePleasant3.9
Late July to August is typically 15 to 24 °C (59 to 75 °F). Mostly comfortable. · Low confidence
- Weather reliabilityVariable3.2
UK summer weather. 2012 was cold and wet in reader memories, but the dock swim has run each year in the sources. · Low confidence
- Venue beautyPleasant3.3
Docklands and ExCeL are plain. Only the Westminster bike route adds landmark views. · Medium confidence
- Spectator friendlySome viewpoints3.0
Good at the swim and finish, poor for the bike, and hard to move between sections. · Medium confidence
Course traits, not part of the score
- Low altitudeSea level5.0
About 5 m (16 ft) above sea level. · High confidence
Stay and travel
Hotels, walkability, getting there, and the town around the race. Counts for 10% of the overall score.
- Hotel availabilityGood4.2
Many hotels at ExCeL and across London. Race weekends are busier. · Medium confidence
- Hotel valuePricey2.4
London prices. Past reviewers called the entry pricey and parking is £25 per day. · Low confidence
- WalkabilityWalkable3.9
ExCeL, DLR stations and hotels are beside the venue, but the transition area is huge and walks inside it are long. · Medium confidence
- Travel easeVery easy4.8
London City Airport is 4 km (2.5 mi) away, with DLR and Elizabeth line links. Bikes are restricted on some Tube lines. · High confidence
- LogisticsSome complexity3.3
Friday pack pickup and bike check-in, sprint pickup also Saturday morning, one big venue. Parking must be booked. · Medium confidence
- Town and foodGreat4.5
Central London is a DLR ride away, but the ExCeL area itself is limited. · Medium confidence
Key facts
- Location
- London (ExCeL, Royal Victoria Dock), Greater London, United Kingdom
- Typical month
- August
- Latest or next date
- 21 August 2027
- Organiser
- Independent (PTO / T100 festival; formerly Challenge London and AJ Bell London Triathlon)
- Field size
- About 3,000 athletes
- First held
- 1997
- Distances
- 1.5 km (0.9 mi) swim, 40 km (24.9 mi) bike, 10 km (6.2 mi) run
- Swim venue
- Royal Victoria Dock, next to ExCeL (harbour)
- Water temperature
- 18–21 °C (64–70 °F)
- Wetsuit
- Legal
- Swim start
- rolling (pulse starts about every 2 seconds; ability waves, white caps for less confident swimmers)
- Swim laps
- 1
- Run laps
- 4
- Run shade
- Little; open dock side paths
- Air temperature
- 15–24 °C (59–75 °F)
- Humidity
- Moderate
- Altitude
- 5 m (16 ft)
- Nearest airport
- London City Airport (LCY), 4 km (2 mi) away
- Where to stay
- ExCeL and Royal Victoria DLR, Canary Wharf, Stratford
- Booking
- Many hotels beside ExCeL and DLR stations; prices rise on race weekends. ExCeL car park 25 GBP per day, book ahead (postcode E16 1FR). Bikes face limits on some Tube lines.
What racers and reviewers say
- Brandworkz blog (Neil Monahan)Raced 2013 · blog · Positive
Olympic distance finisher in 3:13:51 who found the dock swim chaotic but clean, the traffic-free central London bike flat and scenic (Tower of London, London Eye, Westminster turn), and the atmosphere friendly. Proud and enthusiastic.
“the overwhelming feeling of accomplishment on completing the race”
- 220 Triathlon readers' memoriesRaced 2014 · article · Mixed
Six reader stories from 2014. Sprint first-timers called the bike and run easy and the swim cold and grey; an Olympic racer called the swim terrible but praised the atmosphere; one rider had a bike stolen from a hotel on race morning and borrowed a replacement.
- Law GazetteRaced 2008 · article · Positive
Third-person report of an Olympic relay with about 400 competitors in the field. Confirms the 1.5 km (0.93 mi) Royal Victoria Dock swim and a bike on the outer Docklands roads. Friendly mood, no problems reported. Old and thin on detail.
- Slowtwitch forum (T100 London thread)Raced 2023 · forum · Mixed
A poster who raced the 2023 Challenge London said age groupers get the better bike route down to Big Ben and back, but the road surface was poor and the age-group run was crowded. Another poster found parts of the course hard to reach as a spectator.
- Slowtwitch (Kevin Mackinnon)Raced 2025 · article · Positive
Practice-swim piece before the 2025 edition. An algae scare was cleared by testing well below World Triathlon thresholds; water about 20 °C (68 °F), so wetsuits likely. Says the event once drew over 12,000 and the age-group field has recovered somewhat.
Show 1 more
- T100 London athlete informationRaced 2026 · article · Positive
Organiser page for 2026. Pulse swim starts about 2 seconds apart, white caps for less confident swimmers, expected water 18 to 21 °C (64 to 70 °F), traffic-free bike, flat 2.5 km (1.6 mi) run loop, Friday pack pickup, ExCeL parking 25 GBP per day. Marketing source, used for facts only.
Raced London Triathlon (London T100 weekend, ExCeL)? Your notes on the course, conditions and logistics help the next athlete decide.
Sources
Pages we used for facts and ratings. See how we rate.
Training for London Triathlon (London T100 weekend, ExCeL)? Moku Coach builds your plan around race day.