ATW Grafham Triathlon
Grafham Water, Huntingdon, United Kingdom · September · Independent (ATW Events)
Course: 1.5 km (0.9 mi) swim, 38 km (23.6 mi) bike, 10 km (6.2 mi) run. 1,500 m (0.93 mi) swim, 38 km (23.6 mi) bike, 10 km (6.2 mi) run
Why people love it
- One venue for swim, bike and run: Grafham Water Visitor Centre.
- Sprint is one 750 m (0.47 mi) swim lap, 17 km (10.6 mi) bike, 5 km (3.1 mi) run.
- Standard is a full Olympic 1.5 km (0.93 mi) swim, 38 km (23.6 mi) bike, 10 km (6.2 mi) run.
- Flat 5 km (3.1 mi) lap across the dam wall with reservoir views.
- Wetsuit hire and camping the night before are offered.
Watch out for
- Swim entry and exit were muddy for about 100 yd (90 m (295 ft)) when the reservoir was low.
- Wind and the Ellington hill test riders; cars on the climbs reported on open roads.
- Queues for parking exit, registration paperwork and transition.
- Toilets are far from the run, and the village is small.
- The 38 km (23.6 mi) standard bike is 2 km (1.2 mi) short of a full Olympic.
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: Tough
- Racer satisfactionLoved4.2
Racecheck shows 26 ratings at 4.5 and written reviews at 4.6; muddy swim, wind and queues keep it level with other ATW events. · Medium confidence
- OrganizationWell run4.2
Reviewers praise friendly stewards and organisation; queues at parking, registration and transition, and weak wetsuit rinse water, are the gripes. · Medium confidence
- First timer friendlyDoable3.4
Two swim laps and a 38 km (23.6 mi) open-road bike. · Low confidence
Course traits, not part of the score
- PR potentialFast3.6
Mostly flat out-and-back with some climbs. · Low confidence
Swim
Wetsuit odds, water temperature, calm, and the experience of the start. Counts for 16% of the overall score.
- Wetsuit legalUsually4.4
Late-September reservoir water is normally cool, and wetsuit hire is advertised; British Triathlon bans them above 24.6 °C (76.3 °F). · Low confidence
- Water temperatureAcceptable3.2
Late-September reservoir water, estimated 14 to 17 °C (57 to 63 °F). · Low confidence
- Calm waterSome chop3.4
Open reservoir exposed to wind; no chop reports. · Low confidence
- Swim easeEasy3.6
Two 750 m (0.47 mi) laps. · Medium confidence
- Swim experienceGreat3.5
Water described as clean and clear, but a muddy 100 yd (90 m (295 ft)) entry and exit. · Medium confidence
- Swim supportGood3.7
Wave starts at a reservoir with wetsuit hire offered; reviewers mention a muddy entry and exit, not support quality. · Low confidence
Bike
Road surface, closures, scenery and wind. Counts for 18% of the overall score.
- Road surfaceMixed3.4
Not described; mud on the course noted. · Low confidence
- Road closuresMostly open2.0
Open roads; cars on the climbs were noted. · Medium confidence
- Bike sceneryBeautiful3.6
Organiser calls the bike scenic; countryside roads. · Low confidence
- WindSome wind2.5
Open East Anglian terrain; wind was mentioned in 2026. · Medium confidence
Course traits, not part of the score
- Bike speedFast3.8
Out-and-back to St Neots. · Low confidence
- Bike flatnessRolling3.2
Longer course with the same climbs. · Low confidence
- Bike simplicityMostly simple4.0
Out-and-back route with simple turnarounds. · Medium confidence
Run
Crowds, aid stations, conditions underfoot and scenery. Counts for 13% of the overall score.
- Crowd supportDecent3.2
Dam wall lap passes transition and finish; friendly stewards. · Low confidence
- Aid stationsStandard3.4
Not detailed; reviewers asked for toilets nearer the run. · Low confidence
- Run sceneryBeautiful4.0
Dam wall with reservoir views. · Medium confidence
- Run conditionsModerate3.3
Natural footpaths, two laps. · Medium confidence
Course traits, not part of the score
- Run flatnessMostly flat4.3
Same flat lap repeated twice. · Medium confidence
Conditions
Air temperature, how predictable the weather is, setting, and spectating. Counts for 13% of the overall score.
- Air temperatureWarm or cool3.4
Late September highs of about 14 to 18 °C (57 to 64 °F). · Low confidence
- Weather reliabilityVariable3.0
Autumn UK weather; wind and mud reported. · Low confidence
- Venue beautyLovely3.9
Reservoir-side visitor centre and dam wall. · Medium confidence
- Spectator friendlyEasy3.9
Run laps pass transition and finish; one venue. · Medium confidence
Course traits, not part of the score
- Low altitudeSea level4.8
About 40 m (130 ft) above sea level. · Medium confidence
Stay and travel
Hotels, walkability, getting there, and the town around the race. Counts for 10% of the overall score.
- Hotel availabilityGood3.6
Hotels in St Neots and Huntingdon; camping on site. · Low confidence
- Hotel valueNormal3.4
No race-specific data. · Low confidence
- WalkabilityWalkable4.2
Everything at the Visitor Centre; parking on site. · Medium confidence
- Travel easeOne connection3.0
Luton airport is about 65 km (40 mi) away; most drive. · Medium confidence
- LogisticsSimple3.6
Single venue; queues for parking exit and registration papers noted. · Medium confidence
- Town and foodFine2.8
Grafham is a small village; visitor centre cafe. · Low confidence
Key facts
- Location
- Grafham Water, Huntingdon, Cambridgeshire, United Kingdom
- Typical month
- September
- Latest or next date
- 25 September 2027
- Organiser
- Independent (ATW Events)
- Distances (non-standard)
- 1.5 km (0.9 mi) swim, 38 km (23.6 mi) bike, 10 km (6.2 mi) run
- Swim venue
- Grafham Water reservoir (reservoir)
- Wetsuit
- Legal in practice (wetsuit hire offered)
- Swim start
- wave start
- Swim laps
- 2
- Bike laps
- 1
- Key climbs
- Ellington hill; two further climbs
- Run laps
- 2
- Air temperature
- 10–18 °C (50–64 °F)
- Altitude
- 40 m (130 ft)
- Nearest airport
- London Luton (LTN), 65 km (40 mi) away
- Where to stay
- St Neots, Huntingdon
- Booking
- Day-trip race; camping the night before at Lakeview Paddock.
What racers and reviewers say
- RacecheckRaced 2026 · aggregator · Positive
Ten written reviews from 2025 and 2026 (five sprint, five standard) average 4.6 out of 5, with 26 ratings overall at 4.5. Reviewers praise friendly stewards, organisation and a good bike route. Gripes include a muddy 100 yd (90 m (295 ft)) swim entry and exit when the reservoir was low, wind, the Ellington hill, queues at parking and transition, and toilets far from the run.
Raced ATW Grafham Triathlon? 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.
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