ATW Centurion 100KM Triathlon Box End

CHALLENGE YOURSELF TO TACKLE A 100KM CENTURION IN 2026!

JOIN US ON SUNDAY 24th MAY 2026 FOR A UNIQUE EVENT EXPERIENCE DELIVERED BY THE LARGEST MULTISPORTS ORGANISER IN THE UK!

The Metric Centurion distance involves a 2.2km swim in the crystal clear Box End Lake, an 81km road bike on fast country roads, and finishing with a 20km offroad run. This 100K triathlon distance being made popular by the PTO race series, is ideal for anyone who is training for a 70.3 Half-Iron distance or simply wanting to take the next step up from a Standard distance triathlon.

Alongside this unique challenge, you can also take on the usual distances of a:
- Standard Triathlon (1.5k swim, 40k Bike, 10k run)
- Sprint Triathlon (750m swim, 26k Bike, 5k run)  Bookable via our Box End Triathlon page 

Anyone who doesn't want to take part in the run, there is an Aquabike (swim-bike) option for the Metric Centurion, and for those who would like to compete as a team, there is a relay option, with or 2 or 3 individuals sharing the disciplines between them.

This event has a non-draft legal bike leg.

Camping is now available at Box End Park. For more information and to book your camping tickets, email [email protected]

How long can you expect to be racing for?
There is a swim cut-off of 2hrs30 - most people complete the swim in under 1hr10
The bike cutoff is 6hrs30 (from race start) - most people complete the bike in 3hrs
The final race cut off is 8hrs30 (from race start) - most people complete the run in 2hrs30

Transgender athletes are, and will continue to be, very welcome at recreational and competitive activity in Triathlon. At any competitive event from 1st January 2023, there will be a Female category open to athletes who are the female sex at birth and an Open category open to all other athletes.

Want to hire a wetsuit for the season? We are proud to offer Zone3 wetsuits. Find out more HERE

Want to hire a wetsuit for a day, weekend or month? Find out more HERE

Reasons to enter this event:

Beautiful venue

Crystal clear waters

Well marked course

Supportive marshals

FREE event photos

Custom designed medal

Finish line snacks & goodies

Read reviews on Racecheck

 

Charity - Join us in making every stride count by raising money for our partner charity, Alzheimers Research UK - your run will not only challenge your limits but also change lives, one step at a time, for a cure. Opportunities to donate and fundraise will appear at checkout.

 

ATW Transfer & Refund Policy

At ATW, we understand that sometimes plans change. While we do not offer refunds or transfers to another person, we provide a hassle-free event transfer option for those unable to attend their booked event. If you are unable to participate in your scheduled event for any reason—including injury, illness, pregnancy, bereavement, or other unforeseen circumstances—you can transfer your entry to any future ATW event. There is no proof required, we trust you!
Even better news, transfers can be made all the way up to 48 hours before your original event date.

Event Organiser

ATW was established in 2011 by James Shipley. We have now become a national events company in the UK, specialising in Running, Triathlon, Duathlon, Aquathon, Cycling, Swimming and all permutation of swim-bike run events. With over 40,000 entries a year ATW has become a firm favourite amongst people who are determined to Dream, Believe and Achieve.