The Series

The Festival of Endurance

Sunday 7th July 2019 promises another exhilarating and atmospheric celebration of ‘going long’ at the iconic and stunning Hever Castle. Loved by competitors and spectators alike the event is hailed the most friendliest and beautiful on the tri radar.

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The Festival of Endurance

Sunday 7th July 2019

We are pleased to announce that the Festival of Endurance will return on Sunday 7th July 2019.

Due to popular demand the Gauntlet half iron distance triathlon is returning with athletes racing alongside the full iron distance or Bastion competitors around much the same course.  Whilst these two epic triathlons are taking place a further 4 sets of endurance challenge races are taking place including an Aquabike, an Aquathlon, Long Distance Running and Long Distance Swimming making this a true celebration of the art of “going long”.  Please read on for more details.

The Bastion

3.8km/180.2km/42.2km – Full iron distance race.

Set in close proximity to London and in the heartland of Henry VIII’s old hunting grounds, each leg of the Bastion has been designed to offer the ultimate physical challenge to athletes but in the most beautiful setting. The Bastion, which were the final strongholds of medieval castles, features an iridescent 3.8km river and ornamental lake swim, a true toughie of 180km bike course with 2,700m of climbing and a 42.2km trail run that takes place largely off road and incorporates the gardens of both Hever and Chiddingstone Castles. You won’t get a personal best over this distance but you will have the bragging rights to arguably one of the toughest and most iconic races of its kind anywhere in the world.

The Gauntlet

1.9km/90km/21.1km – Half iron distance race.

The half iron distance equivalent of the Bastion, we call the Gauntlet, was 2018’s venue for the British Middle Distance Championships and filmed by Channel 4.  Again no chance of a PB on this super-tough course but you will have undertaken a huge challenge of one of Europe’s most beautiful races.

Long course training distances

We are offering you the chance to swim, bike or run sections of The Bastion, arguably the most grueling Full Iron distance course on the planet. Fully timed and fully supported just like those taking on the iron-distance race alongside you.

The perfect training ground to prepare for any iron-distance challenge or to get an idea of what might await you next year should you return for the ultimate Castle Triathlon Series challenge and take on The Bastion in 2019. This is a fantastic training race set in a stunning location in mid-summer, perfect for those taking on an iron-distance in the second half of the year.

The Aquabike Challenge


  • 1.9k swim: 60k cycle: 4k optional run (Laps 1:1:1)
  • 3.8k swim: 120k cycle: 4k optional run (Laps 2:2:1)

There’s a training option for everybody who’s into long distance.  After the unique swim you’ll head out on the fully marshalled and signed bike course with supported feed stations. This circular cycle route will take competitors out of Hever Castle, up through the High Weald of Kent before passing through and over the Ashdown Forest and into the village of Maresfield.  After a quick tour of the village competitors retrace their steps to the top of the forest before returning to Hever via the historic and quintessentially English villages of Groombridge, Fordcombe and Penshurst.  Finishers have the option of finishing with a gentle 4K run that circumnavigates the lake and stunning grounds of the Hever estate.

The Aquathlon Challenge


  • 1.9k swim / 10k run (Laps 1:1)
  • 3.8k swim / 21k run (Laps 2:2)

After the unique swim (1 or 2 loops), competitors will then embark on the 10k/21km run course, which follows largely off road tracks and bridle paths between Hever Castle, through the historic local village of Chiddingstone, before finishing right in front of the Castle.

The Duathlon Challenge


10.5km / 45km / 4km (Laps 1:1:1)
21.5km / 90km / 10.5km (1:2:1)

After a unique run (1 or 2 laps) through the glorious Kent countryside and around the private estates of Hever and Chiddingstone Castles, cycle up to the highpoint of the Ashdown Forest (1 or 2 laps) before finishing off with further laps of the beautifully manicured gardens and local network of paths and trails.

The Hever Marathon

26.2 miles

After the huge success of the inaugural event in the 2018 Series, the marathon returns to the atmospheric Festival of Endurance at Hever Castle.

Forget the city marathon, and fill your lungs with country air and stunning scenery before you conquer your marathon by a castle drawbridge. This new marathon, promises the most stunning off road course in the UK, a truly motivational and beautiful route that will distract you from the challenge itself. The four-laps take in two castles, two lakes, quaint Kentish villages, oast houses and with spectators and locals cheering you on all the way!

Marathon Pacer Timings : 4.00hrs, 4.30hrs, 5.00hrs, 5.30hrs (this is slower paced course than many road ones –  4.30hrs on this course is equivalent to a 4.00hrs on a road course!)

The Hever Half Marathon

13.1 miles

Take on the half marathon at our 2019 Festival of Endurance, on the most stunning off road course in the UK.

Starting at the drawbridge of the Hever Castle, this two-lap course takes in two castles, two lakes, quaint Kentish villages, oast houses with spectators and locals cheering you on all the way! Finish your race with a big celebration, medal and finishing line banquet in sight of the castle.

Half Marathon Pacer Timings : 1.45hrs, 2.00hrs, 2.15hrs, 2.30hrs

The Hever Long Distance Swim


  • 1.9k circuit
  • 3.8k circuit
  • 10K Marathon Swim (NEW in 2018) Entry tickets available to Individuals and Relay team of 5 (each team member takes on the 2k loop circuit).

The swim course leaves from the Italianate loggia taking competitors down the length of the main lake and heading into the scenic river section.This tributary of the River Eden wraps around 16 Acre Island allowing spectators to watch and cheer competitors on from only a few meters away. The Speedo team will be on hand to welcome you at the finish, then it’s time to relax and enjoy a complimentary bacon roll back at the Event Village.

2019 Race distances and pricing

Race Name
Race Distance
Race Price
(Individual / Relay)
Discount Prices
(Individual / Relay)
Start time
The Bastion Full Iron Distance
£360 / 450
£270 / 338
The Gauntlet Half Iron Distance
£220 / 270
£165/ 203
Middle Distance Aquabike (Swim / Bike)
1.9km swim / 60km bike (optional 4km run)
Long Distance Aquabike (Swim / Bike)
3.8km swim / 120km bike
Middle Distance Aquathlon (Swim / Run)
1.9km swim / 10km run
*Long Distance Aquathlon (Swim / Run)
3.8km swim / 21.5km run
Half Marathon
21.1km run
Full Marathon
42.2km run
Middle Distance Duathlon (Run / Bike / Run)
10.5km / 45km / 4km
Long Distance Duathlon (Run / Bike / Run)
21.5km / 90km / 10.5km
Middle Distance Swim
1.9km swim
Long Distance Swim
3.8km swim
Swim Marathon
10K Swim
£75 / 125
£56 / 94

Start times are approximate and shown here as a general guide. These are subject to change. Each distance start time is preceded by a brief by the Race Director.

Relay options apply for 10K Swim, Gauntlet and Bastion competitors.

Entrants will be notified via email with full race details, including confirmation of wave times, 2 weeks prior to the event.

*The Long Distance Aquabike includes an optional 4km run.

Race day information

Two weeks prior to event, this section will give you everything you need to know about race day, including wave times, registration opening details, spectator entry, camping info and water temperature readings etc.

Course maps

Please take a moment to study these in details.

The Festival of Endurance at Hever Castle is an exciting and busy event with lots of different courses taking place throughout the day. There will be a full brief before your race start but it’s a good idea to familiarise yourself with the course and in particular any key junctions to ensure you take the correct route.

2018 Results

Congratulations to everyone who took part in the 2018 triathlon festival! We hope to see you in 2019.

This section will provide you with the 2018 race time results.

Useful information

Race licence

The Castle Triathlon Series UK events are governed by the British Triathlon Federation and their technical officials will provide guidance on the day and in the run up to the event.

On race day, all participants involved in a multi-discipline sport are required to produce a valid triathlon governing body membership card or purchase a Day Licence. The Day Licence fee is £5 Adult £1 Child and can be purchased at Registration on event day.  More information here

Spectator Offering

The spectator experience at the Castle Triathlon Series has become almost as famous as the spectacular backdrops and classic courses, and has made passing time before your loved ones finish the race a thing of the past.

Travel, accommodation and directions to the venue

Click the link below to find out everything you need to know about all of our venues.

Water quality

Please see the latest water quality tests for Hever Castle lake. All tests are undertaken using the EU Water Bathing Directive as the benchmark.

Water temperature

This will be taken nearer the Event, and posted on the Race Admin page.

Race distances

Race distances

For the absolute beginners and children to the professional triathletes, the Castle Triathlon Series offers a wealth of race distances to suit all levels.

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Hosted at a selection of stunning and iconic castles across the UK, Ireland and France, the Castle Triathlon Series events all promise an inspirational and memorable race experience.

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Take part

We pride ourselves on offering a bespoke and tailored offering for all those wishing to take part and grateful for all those who want to be involved on the day.

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We would always recommend training in preparation for any event, but how much you do, and the style you take is down to you.

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