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100,000 athletes & counting: Castle Triathlon Series celebrates 10 years

Hever Castle triathletes swim start

The Castle Triathlon Series is celebrating its 10-year anniversary this year having hosted its first event, Hever Castle Triathlon, in 2009 with 1,100 competitors.

The UK-based triathlon series will host an estimated 18,000 competitors across six weekend events in the UK, Ireland and France in 2018. The Hever Castle Triathlon has grown by a significant 500%, and is now billed as the third largest triathlon in the UK with over 6,000 competitors. It’s also been recognised as ‘the world’s largest junior triathlon’.

A major milestone for the event organiser, celebrating its anniversary is that 100,000 athletes are reported to have completed a Castle Triathlon Series event. The has also been a reported 10% increase in female competitors, and over £1,000,000 raised for charity overall.

By the numbers:

  • 100,000 total competitors who have taken part in a triathlon with the Castle Triathlon Series
  • 18,000 junior triathletes
  • 5,900 winners on the podium
  • 33,000 women triathletes competed – grown by 10% since 2009
  • 19,400 gave it a tri for the first time
  • Helped raise over £1,000,000 for charity
  • 1,750 primary school children, and 70 schools, taken part in the community tri training roadshows
  • 100 Keep Loyalty Club members (competed in ten or more races since 2014)

Bailey Matthews at Castle Triathlon Series

Brian Adcock, Castle Triathlon Series Founder and Race Director said “Triathlon and family friendly festivals will continue to be at the heart of the Castle Triathlon Series offering. Our growth will come organically from nurturing novices at one end, whilst hosting more qualifying races at the top end to attract age groupers and serious athletes.

“At the same time we will start to offer solus runs and swims during the event weekends aiming to appeal to the wider running and swimming market, as well as injured/training constrained triathletes. The runs will form The Castle Run Series and include a 10K, half marathon and at Hever Castle in July a full marathon. The swims will also have three distances; 1 mile, 5k and 2.5k and will be trailed as the Castle Swim Series.”



The series claims a notable 43% return rate (36% return for the Bastion Iron Distance event). According to the organiser, this is ‘testament to its stunning locations, festival offering and event atmosphere.’

Top 10 features about the last 10 years

  • Grown from 1,000 to 18,000 annual competitors
  • Expanded from one to five iconic castle locations
  • Offers 10 different triathlon distances across the event weekend
  • Camping and festival are central themes; last year saw 1,000 campers at Hever Castle alone
  • The Castle Triathlon Series created the first curriculum-linked primary school resources for triathlon (Tri Knights) and subsequently created materials for Triathlon Scotland, Welsh Triathlon and Triathlon Ireland helping them grow their junior triathlon membership
  • The series embraces diversity. ‘This was borne out in glorious technicolour when competitor Bailey Matthews (an eight-year-old with cerebral palsy) rose to global fame and was awarded the BBC Personality of the Year Award after competing in the 2015 Castle Howard Triathlon.’
  • Introduced the Keep Loyalty Scheme recognising people who have returned year-on-year to the series, helping to bolster the 43% loyalty rate
  • One of the first race organisers to introduce Mixed Team Relay races (short triathlon for each of four team members) to celebrate the format adopted at the 2020 Tokyo Olympics
  • First timers, novices and female competitors are a key focus with the Starter Tri field growing at 30% year-on-year
  • Hosted more than ten qualifying races including the British Middle Distance Championships at Hever Castle on 8th July 2018

Throughout its anniversary year the Castle Triathlon Series will ‘share stories about amazing inspirational people who having given it a tri with us over the last ten years and benefited from the experience; whether to help charity, their wellbeing or create a legacy.’ All Castle Triathlon Series, Castle Run Series and Castle Swim Series race entries are currently on offer at a 15% discount.



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