Le Bastion (Château de Chantilly Iron Distance)
Chantilly, France · June · Castle Race Series (Independent)
Why people love it
- Iron-distance race beside the Château de Chantilly with a shaded run through the gardens
- Marshals and gendarmes on junctions let riders keep rolling on open roads
- Well-stocked bike aid and friendly volunteers praised by finishers
- Large multi-race weekend atmosphere
Watch out for
- Distances questioned: reviewers say the bike or run may not measure 180 km (112 mi) or 42.2 km (26.2 mi)
- Run has only a few aid stations and a hill at about 3 km (1.9 mi) per lap
- Courses overlap with other races: crowding, signage gaps and one extra loop ridden in 2026
- Algae in the canal and potholes or gravel near transition
Race
How racers feel about it, how well it is run, and how it treats a first timer. Counts for 27% of the overall score.
- Racer satisfactionLoved3.9
Seven reviews from 2025 and 2026 average about 4.1 out of 5: beautiful site and volunteers, with course-measurement and finish-area complaints. · Low confidence
- OrganizationWell run3.5
Fluid and friendly for most, but overlapping races, a missed finish announcement and missing run supplies show gaps. · Low confidence
- First timer friendlyDoable2.7
A first full finished happily with clear marshalling, though the hill-laden run and sparse aid add difficulty. · Low confidence
Course traits, not part of the score
- PR potentialAverage3.0
Shaded, mostly rolling course, but questions about measured distances make times hard to compare. · Low confidence
- Course easeTough2.6
Rolling bike and a hilly four-lap run. · Low confidence
Swim
Wetsuit odds, water temperature, calm, and the experience of the start. Counts for 15% of the overall score.
- Wetsuit legalAlmost always4.5
June canal water is cool; wetsuits are used but temperatures are not published. · Low confidence
- Water temperatureAcceptable3.0
Cool June canal water with algae; no recorded temperature for the full. · Low confidence
- Calm waterMostly calm4.4
Sheltered canal; algae and branches are the issue, not chop. · Low confidence
- Swim easeModerate3.1
Wave starts and algae, but a straight canal course. · Low confidence
- Swim experienceMeh2.3
Water quality described as imperfect and algae-affected. · Low confidence
Bike
Road surface, closures, scenery and wind. Counts for 19% of the overall score.
- Road surfaceMixed2.8
Potholes and gravel on the road to and from transition. · Low confidence
- Road closuresPartly closed3.4
Open roads with police and volunteers on junctions; cars in Senlis could back up. · Medium confidence
- Bike sceneryBeautiful4.3
Forest and château landscape. · Low confidence
- WindSome wind3.2
No wind complaints. · Low confidence
Course traits, not part of the score
- Bike speedFast3.6
Roads described as secure and fast, with a rough zone near transition. · Low confidence
- Bike flatnessRolling3.2
No elevation total published; reviewers do not describe it as hilly. · Low confidence
- Bike simplicitySome technical parts2.9
Repeated loops and overlapping races led to a mis-sort for one rider. · Low confidence
Run
Crowds, aid stations, conditions underfoot and scenery. Counts for 13% of the overall score.
- Crowd supportStrong3.8
Festival atmosphere with many races on the same weekend. · Low confidence
- Aid stationsGood3.7
Bike aid well stocked; run aid gap criticised. · Low confidence
- Run scenerySpectacular4.6
Château gardens and forest. · Medium confidence
- Run conditionsModerate3.0
Shaded and varied but crowded and with aid spacing complaints. · Low confidence
Course traits, not part of the score
- Run flatnessRolling2.7
A demanding hill at about 3 km (1.9 mi) per lap. · Low confidence
Conditions
Air temperature, how predictable the weather is, setting, and spectating. Counts for 15% of the overall score.
- Air temperaturePleasant3.9
Early-June France; shade on the course. · Low confidence
- Weather reliabilityReliable3.5
Two editions held without reported weather problems. · Low confidence
- Venue beautyStunning4.9
The château is the central draw. · Medium confidence
- Spectator friendlyEasy3.8
Gardens and village help, though long distance spectating is spread out. · Low confidence
Course traits, not part of the score
- Low altitudeSea level4.9
Chantilly lies 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 11% of the overall score.
- Hotel availabilityBook early3.4
Chantilly and Senlis lodging; busy race weekend. · Low confidence
- Hotel valueNormal3.2
No cost comments. · Low confidence
- WalkabilitySome driving3.4
Parking close to the site per a 2026 reviewer. · Low confidence
- Travel easeEasy4.0
About 30 km (19 mi) from Paris CDG with a rail link. · Medium confidence
- LogisticsSome complexity3.0
Overlapping races, a missed bag area and a missing finish meal were noted. · Low confidence
- Town and foodGood3.9
Chantilly offers restaurants and the estate. · Low confidence
Key facts
- Location
- Chantilly, Hauts-de-France (Oise), France
- Typical month
- June
- Latest or next date
- 13 June 2027
- Organiser
- Castle Race Series (Independent)
- First held
- 2025
- Distances
- 3.8 km (2.4 mi) swim, 180 km (112 mi) bike, 42.2 km (26 mi) run
- Swim venue
- Grand Canal, Château de Chantilly (canal)
- Wetsuit
- Legal
- Swim start
- wave
- Run laps
- 4
- Run shade
- shaded
- Altitude
- 40 m (130 ft)
- Nearest airport
- Paris Charles de Gaulle (CDG), 30 km (19 mi) away
- Where to stay
- Chantilly, Senlis
- Booking
- Hotels in Chantilly and Senlis; book early because a large multi-race weekend fills lodging.
What racers and reviewers say
- RaceCheck: Bart W.Raced 2026 · aggregator · Positive
First full distance. The swim was okay with imperfect water quality, the bike very well organised with marshals and police on every junction so he never stopped, though the road to and from transition was potholes and gravel. Nice run; wants spread-out feed stations. Finish aftercare disappointing, with no promised meal.
- RaceCheck: Aurelien K.Raced 2026 · aggregator · Positive
Great ambiance and very fluid organisation with accessible organisers, a well-shaded course, good parking and low stress. Wants correct 180 km (112 mi) and 42.2 km (26.2 mi) distances, a run aid station, volunteers at tables, less algae, and notes some traffic jams in Senlis.
- RaceCheck: AnonymousRaced 2026 · aggregator · Positive
Thanks the organisers and gendarmes: route well marked and framed, drivers respectful, bike aid well stocked, run aid impeccable and a demanding climb at 3 km (1.9 mi) each lap. Swim had less algae than last year, parking and toilets fine; wanted a clear transition-bag area.
- RaceCheck: Vabois M.Raced 2026 · aggregator · Mixed
Bike course lacked signage at the end with many races overlapping, so he rode an extra 20 km (12.4 mi) loop after 180 km (112 mi) because no marshal sorted the riders. Run finish zone had spectators and a stroller between barriers, and a crossing with other races was unsafe. Still a very good triathlon.
- RaceCheck: Julie N.Raced 2026 · aggregator · Mixed
Women's XXL winner who liked the kind volunteers, atmosphere and well-marked course, but was disappointed that her finish was not announced, her T-shirt was too large and her personal run supplies went missing.
Show 2 more
- RaceCheck: AnonymousRaced 2026 · aggregator · Positive
Beautiful organisation with helpful, friendly volunteers. Felt safe on the bike thanks to marshals and gendarmes at dangerous junctions; the site is exceptional, the run great, the swim rather particular. Wants a run aid station because the gap between the last and first stations was too long.
- RaceCheck: Franck B.Raced 2025 · aggregator · Positive
Has come to Chantilly for ten years and called the Bastion the ultimate challenge, with superb organisation and top volunteers on course and at aid stations.
Sources
Pages we used for facts and ratings. See how we rate.
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