When is the 2027 Chantilly triathlon?

On Saturday 12 and Sunday 13 June 2027, according to the Castle Race Series. The Olympic distance, the half and the iron distance are on Sunday; the short formats and youth races on Saturday. The 2026 edition took place on 6 and 7 June.

How much is the entry?

Full price for 2027: €140 for the Olympic solo (€240 as a relay), €260 for Le Gantelet, €400 for Le Bastion, €60 to €110 for the Saturday formats.

Where is the Chantilly triathlon swim?

In the château’s Grand Canal, a 2.5 km-long canal that feeds into the Oise. According to the organiser, a wetsuit is very likely to be mandatory.

No. The series rules require 12 m between two bikes, and the roads stay open to traffic: the highway code applies.

Triathlon de Chantilly (Castle Race): how many weeks of preparation?

For an athlete at intermediate level, Endu builds a 15-week preparation. If your race is closer, the plan compresses phases while keeping the taper; if it's further away, it lengthens the preparation, and when the gap is large the preparation starts right away, gently and at your current volume, before building up.

How many sessions per week?

This example has 5 sessions per week. You choose 4 to 7 training days and the exact days (e.g. Tue, Thu, Sat, Sun): the plan sticks to them.

I'm a beginner, is this plan for me?

The plan adapts to your declared level (beginner to semi-pro): starting volume, progression and intensity change. Endu also offers a "Discovery" mode without a race to build a base first.

Can I follow sessions on my watch?

Yes, on Garmin and COROS. On Garmin, the Endu app (Connect IQ Store) shows today’s session and starts it as a guided workout. On COROS, link your account from your profile: your running, trail and cycling sessions land in the watch calendar. Other brands are not supported yet.

How much does it cost?

14-day free trial, then €7.99/month with no commitment or €59.88/year (€4.99/month). Unlimited objectives and sports.

Triathlon de Chantilly (Castle Race) 2027: date, course and training plan

51.5 km · swim 1.5 · bike 40 · run 10Chantilly2027 edition: 13 June 2027

The Château de Chantilly triathlon is part of the Castle Race Series, a British series of races held in castle grounds. Over two days in June, you swim in the Grand Canal below the château, ride around the Forêt de Chantilly and run in the park. Sunday brings together the Olympic distance, the half (Le Gantelet) and the iron distance (Le Bastion); in 2026, nearly 7,000 competitors took part over the weekend.

Your plan for Triathlon de Chantilly (Castle Race)

32 weeks to go: your plan starts this week, set to your level and free days, then adapts to your feedback after each session.

Your level?

14-day trial, cancel anytime.

Triathlon de Chantilly (Castle Race) at a glance

Date: 2027 edition: 13 June 2027
Formats: OlympiquePlan below — 1.5 km swim, 40 km bike, 10 km run, on Sunday afternoon. €140 solo, €240 as a relay (full price). Cut-offs: out of transition within 3h15, finish within 4h15, only enforced when safety requires it. In 2026, 1,277 triathletes started, in seven waves.
Le Gantelet — Half distance: 1.9 km swim, 90 km bike, 21 km run, on Sunday. €260 solo, €330 as a relay. Cut-offs: swim within 1h30, out of transition within 7 hours, finish within 10 hours.
Le Bastion — Iron distance: 3.8 km swim, 180 km bike, 42.2 km run, on Sunday 13 June 2027 (7 am start in 2026). €400 solo, €500 as a relay. Finish within 16 hours.
Formats courts du samedi — Le Condé Plus (800 m / 40 km / 8 km, €110), Sprint (750 m / 20 km / 5 km, €95), Super Sprint Louis XV (400 m / 20 km / 4 km, €80) and Starter Découverte (200 m / 20 km / 2.5 km, €60), solo or as a relay.
Duathlon, course à pied, nage et jeunes — An M duathlon (€100), a marathon, a marathon relay, a half marathon, a 10K and a 5K in the park, open-water swims from 1 mile to 5 km, and triathlons for 8 to 15-year-olds on Saturday (€25 to €35).
Registration: Entries for 2027 are open on the Castle Race Series website. The prices shown are full prices: €140 for the Olympic solo, €240 as a relay; the organiser runs occasional discounts. Every triathlete must upload their licence online before the race, and the event is endorsed by the FFTri; the details of the 2027 documents are announced as “coming soon”.
Official website: castleraceseries.com/events/chateau-de-chantilly-fr

The 2026 course

Start in the Grand Canal, below the château’s formal gardens, with marked out-and-back legs in the arms of the canal. Bike (2026 Sunday map): a loop of about 20 km, for 40 km in all on the Olympic, which leaves the estate towards Courteuil and Saint-Nicolas-d’Acy, skirts Senlis, climbs towards Aumont-en-Halatte and the Butte d’Aumont, passes Apremont and comes back down via Vineuil-Saint-Firmin. Run: a 10.5 km loop in the park, via the Hameau, the Maison Forestière de la Porte, the Petit Labyrinthe, La Fourrière, the edge of the Grandes Écuries and the Île d’Amour, finishing in front of the château.

What the race asks of your training

A swim where a wetsuit is very likely

In early June, the organiser warns that wetsuits will very likely be mandatory in the Grand Canal (FFTri rule: mandatory below 16 °C). Swimming three or four times in open water in the spring, in your race wetsuit, saves you from discovering the cold and the tight shoulders on race morning.

A rolling bike course, on open roads

The Sunday loop runs through the forest and around Senlis, with a single noticeable climb, the Butte d’Aumont (124 m above sea level). The roads are not closed and drafting is banned: prepare to ride alone, at a steady effort, with 15 to 20-minute blocks at race pace.

A 10K along the park paths

The run is a loop through the château park, between the Hameau, the Labyrinth, the Grandes Écuries and the Île d’Amour. Bricks of bike followed by 20 minutes at 10K pace, every week late in the build-up, teach you to find your rhythm straight out of transition.

An afternoon race, at the start of summer

The Olympic starts on Sunday afternoon, the last race of the weekend; in 2026 the day was hot and sunny. Rehearse one or two key sessions at that time of day, testing what you eat before and during the race.

The plan below prepares the Olympique format, for an athlete at intermediate level with 5 days available per week, with race day on 13 June 2027. Aiming for another format? Enter its distance when you create your plan, which will be calibrated on your level, your available days and your feedback after every session.

weeks: 15
sessions: 74
sessions / week: 5
peak week: 7 h

Plan structure

Periodised in phases: build the base, move to race-specific work, then taper before the race.

General preparation
Weeks 1–2 · 2 wk
Base
Weeks 3–6 · 4 wk
Build
Weeks 7–9 · 3 wk
Specific
Weeks 10–12 · 3 wk
Taper
Weeks 13–14 · 2 wk
Race week
Weeks 15–15 · 1 wk

Volume progression

Week by week: lighter recovery weeks are built in to absorb the load.

Wk	Phase	Hours	km
1	General preparation	4.4 h	17
2	General preparation	4.7 h	18
3	Base	5.3 h	12
4	Base	5.5 h	13
5	Baserecovery	4 h	10
6	Base	5.7 h	13
7	Build	6 h	14
8	Build	6.1 h	15
9	Buildrecovery	4.2 h	11
10	Specific	6.4 h	15
11	Specific	6.8 h	16
12	Specific	7 h	17
13	Taper	5.1 h	18
14	Taper	4.1 h	16
15	Race week	2.4 h	7

Sample week — week 8 (Build)

Real sessions from the plan with their targets. Each session is detailed step by step, and can be sent to a Garmin or COROS watch.

MondaySwimmingEasy
39 min continuous swim
39 min · 1.8 km
TuesdayBrickHard
1 h 05 bike + 45 min run
including 3 × 10 min at threshold on the bike · run at threshold
1 h 58
FridaySwimmingHard
3 × 300 m at threshold
40 s recovery
37 min · 1.7 km
SaturdayCyclingEasy
1 h 44 at endurance pace
1 h 44
SundayRunningEasy
Long run 1 h 09
1 h 09 · 11.1 km

Example generated for a intermediate-level profile (MAS 15 km/h, 5 days available per week). Your plan will depend on your level, availability and feedback.

This plan’s check-up

Pass

A 15-week build (recommended minimum: 8); a longest run never more than 8% above the previous month’s; 83% of the time at easy effort; a taper cutting volume by 66% in race week.

3 worth knowing · 19 checks passed

Remarks

Demanding sessions — Up to 4 demanding sessions in a single week (1 week(s)).
Strength training — No strength session.
Fueling — Long sessions (up to 128 min in this plan) are where race fueling is rehearsed.

The 19 checks passed, in detail

Length of the build — 15 weeks: enough for this race (recommended minimum: 8).
Sessions per week — 5 sessions a week: the minimum for this race is met.
Volume progression — Running volume rises smoothly from week to week.
Long run increase — Each week, the longest run is at most 8% longer than the longest of the previous month (benchmark: 10%).
Lighter weeks — A lighter week comes back regularly (weeks 5, 9, 13).
Intensity distribution — About 83% of the time at easy effort: the most common distribution among trained endurance athletes.
Hard days back to back — Demanding sessions are separated by easy days.
Rest days — At least one rest day a week.
Bike-run bricks — 10 bike-run bricks over the last 12 weeks.
Taper — Volume drops 66% in race week.
Intensity during the taper — Short race-pace efforts remain in the last two weeks.
Frequency during the taper — The number of sessions stays close to usual (90%).
Swim / bike / run balance — Swim 21%, bike 46%, run 32%: within coaches’ benchmarks.
Frequency per discipline — Each discipline comes back at least 2 times a week.
Open water — 3 open-water session(s) before the race.
Longest ride — The longest ride lasts 120 min (benchmark: 90 to 150 min).
Longest run — The longest run lasts 80 min (benchmark: 60 to 105 min).
Swim distance — The longest swim covers 187% of the race distance.
Long ride increase — The long ride grows in small steps.

Endu runs its own plans through the plan check open to everyone: same public rules, same thresholds, same sources. The rules and their sources, and a check of your own plan.

Why this plan works

Science-based periodisation

Base → build → specific → taper, with a recovery week every 3 to 4 weeks. Load goes up, but never two hard weeks in a row without a breather.

Paces, not vague feelings

Every session has target zones (pace, HR) computed from your MAS or a reference performance. A MAS test is built into the plan if you don't know yours.

Three disciplines, one load

Swim, bike and run are planned together: brick sessions, key sessions spread out, and a coherent total load week after week.

A plan that listens

After each session you rate how it felt (RPE). Too hard? The plan eases what follows. Skipped a session? It reschedules or absorbs it.

On your watch

On Garmin with the Endu app, on COROS by direct sync: the guided workout shows up on your wrist, step by step.

Reviews

What our users say.

4.8/5

“For triathlon, having all three sports in the same schedule really makes my life easier. I spend less time organising my training and I still enjoy following it just as much.”
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Your plan, not a template athlete's

This plan is generated for an athlete at intermediate level with 5 days available per week. Yours will be calibrated on your MAS, your available days and your feedback after every session. 3 minutes. 14-day trial, cancel anytime.

Create my plan for Triathlon de Chantilly (Castle Race)