Pop-up City Triathlon
24-27 April 2017

Lough Cutra Castle
26/27 May 2018

Cholmondeley Castle
23/24 June 2018

The Festival of Endurance at Hever Castle
8 July 2018

Castle Howard
22/23 July 2017

Château de Chantilly
26/27 August 2017

Hever Castle
23/24 September 2017

Schools Roadshow
July 2017


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.

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The Bastion - Full iron distance

Hever Castle, Kent

We are delighted to announce that The Bastion full iron-distance triathlon will be back, for the fifth time, on 8th July 2018. Pre-registration is now open for this iconic and unique event. The nurtured exclusive field continues to shows loyalty and grit and we look forward to welcoming them back along with new competitors ready to take on the challenge. Pre-register now to receive early bird news and benefits.

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 3,000m 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.

220 Triathlon has listed The Bastion as a ‘must-do’ race in 2017.

Get a taster of The Bastion course

Bastion Training Guides

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

Course Maps

Please take a moment to study these in details.

The Bastion is an exciting and busy event with lots of different courses taking place throughout the day. There will be a full brief the day before your race 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.

2017 Results

This section will provide you with the 2017 race time results.

The Bastion was quite simply the best event I’ve ever done. The course was immense; brutal, but brilliant. The venue was unique; an inspiring backdrop and great fun for spectators.
Dan Cliffe

Useful information

Preparation for the event

The 2017 Competitor Guide, tailored for the Bastion at Hever Castle guides the competitor through the preparation for the event.

The Bastion Competitor Guide 2017
The Bastion Spectator Guide 2017
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 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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