Lough Cutra Castle
29 May 2016

Cholmondeley Castle
26 June 2016

The Festival of Endurance at Hever Castle
10 July 2016

Castle Howard
23/24 July 2016

Château de Chantilly
27/28 August 2016

Hever Castle
24/25 September 2016


The Bastion - Full iron distance

The iconic endurance challenge will kick off with a 3.8km lake swim before a 180km bike takes competitors around the Kent countryside. A 42km marathon run completes what will be arguably Britain’s toughest and most rewarding long-distance event.

The Bastion - Full iron distance

At Hever Castle, Kent

10 July 2016

We are delighted to announce that The Bastion iron-distance triathlon 2016, part of the UK’s biggest triathlon series, The Castle Triathlon Series, is now open. The Bastion is set to take place on the 10th July 2016.

For a limited time only, you have the first option to confirm and secure your place at The Bastion, set to take place from the stunning and historic Hever Castle in Kent, at a special early bird rate.

Make sure you secure your place now because The Bastion is set to fill up very quickly after two successful years and the price is set to rise after the early bird discount ends.

Bastion Hever Castle Triathlon Long Distance Half Iron

About The Bastion

3.8km/180.2km/42.2km Following the success of the Gauntlet, which will have over 2000 competitors entering the middle-distance event across the series in this year; the Bastion which take place in July’s mid summer, was a natural progression to feed that hunger for more.

Set within close proximity to London and triathlon’s heartland of the south-east, each leg of The Bastion has been carefully designed to offer the ultimate challenge for both newcomers to long-distance triathlon and experienced long-course hands. The Bastion, the final stronghold of a medieval castle, will feature a 3.8km river and lake swim, a true toughie of a 180km bike course with 2,000m of climbing and a 42.2km run course that takes place largely off-road including running through the grounds of the beautiful Chiddingstone Castle. Following a huge success in 2014 generating rave reviews, the iron distance men and women enhanced the experience in 2015 contributing to growing this event into one of the truly iconic long distance triathlons in the world.

Get a taster of The Bastion course

Bastion Training Guides

RGActive have designed two training plans depending on level of experience of a triathlete and tailored specifically to the  Full Iron ‘Bastion’ distance triathlon.

With this challenging Hever Castle triathlon course in mind, RGActive have also provided these invaluable training guides.


2015 Race results and photography

This section will provide you with the 2015 race time results and links to competitor photography.

I will be entering the Gauntlet at Hever shortly and Bastion again for 2015. The events, although tough, are excellent and much better than the IM branded ones. Thanks again.
Dave Bowden

Useful information

Preparation for the event

The 2016 Competitor Guide, tailored for the Bastion at Hever Castle guides the competitor through the preparation for the event.

The Bastion Competitor Guide 2016
The Bastion Spectator Guide 2015
Trophies, prize money and medals

All competitors in all races will receive a medal on completion of their race.

Each 1st place winner will also receive a suitably themed trophy, and sponsor’s prizes for 2nd and 3rd place. There is a significant prize pot on offer for the Olympic and Gauntlet race distances.

Click below to find out more about what we have on offer.

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.

Rules and Terms and Conditions

Please read and understand the general rules, in particular the cut-off times, before competing to ensure a fantastic race for you and everyone else.

Water quality

Please see water quality tests for Hever Castle lake taken in September 2015. 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.

Find out more


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.

Find out more

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.

Find out more


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

Find out more