Triathlon is better with the right team behind you.
Whether you're crossing your first finish line or chasing a Kona slot, T3 gives you the coaching, the community and the support to get there.
Who are we?
T3 is a global team of triathletes — professionals, age-groupers and first-timers — built around one idea: that coaching should feel personal, training should feel purposeful, and the sport should be genuinely enjoyable. We're passionate, we're competitive, and we're in it together.
Bespoke 1-2-1 Coaching
Get a fully customised training plan delivered via TrainingPeaks, built strictly around your career and lifestyle. We analyse your data daily and adjust your sessions on the fly when life gets busy. By joining the roster, you also gain full integration into the wider T3 community for shared group training and race-day support.
What our athletes say
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“The combination of bespoke training programmes, pro athletes to aspire to, training camps, and a supportive team environment has helped me improve massively — all while genuinely enjoying the process.”
George Rofe
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“I feel super lucky to be working with T3. The mashup of 1-2-1 coaching, pro athletes, and team has brought a fun balance to my training and life over the past few years.”
Josh Allen
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“The T3 crew are a top bunch of people where there are no egos, just a great culture of looking after each other & training hard whilst having fun.”
Nick Cranston
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“I started with Mark as my coach in November and have managed to gain consistency in my training and improve my running so much that I’m now one of the fastest runners in Xterra.”
Morgan Rhodes
Meet the coaches
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Mark Threlfall - Founder
T3 was setup by ex-professional triathlete, Mark Threlfall, who competed at numerous European and World Championships at an elite level for Great Britain, before moving on to a successful long-distance triathlon career.
T3 begun as a hobby for Mark, as he enjoyed helping others embark on their own triathlon journeys. A number of years on and this “hobby” has become a coaching setup, a fun and friendly community, and a well established team.
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Harry Palmer - Coach
Since these early days, Harry Palmer, has joined T3 as a coach. He is a qualified BTF Level 2 Coach, and also an accomplished triathlete himself.
In 2018 he was the fastest Age Grouper overall in Ironman 70.3 Staffordshire and Ironman 70.3 Weymouth. This gave him the confidence to step up to racing professionally in 2019. This journey has been a huge experience for Harry, that he documents through his YouTube channel.
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Will Crudgington - Coach
From his introduction to triathlon, Will has been part of the T3 family and now joins as a BTF Level 2 Coach.
Since 2016, Will has regularly and successfully represented GB over various distances at Elite level. He has recently been competing in off-road (Xterra) triathlon events and showing his range of skills against some of the best in the world. Will looks forward to helping others in the same way T3 has helped him.
Other Services
Alongside 1-2-1 Bespoke Triathlon Coaching, we offer a range of other services to support you.
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Most triathletes plateau in the swim due to poor technique, not fitness. Our dedicated pool sessions capture your stroke from multiple angles to diagnose body position and catching efficiency. You will walk away with a frame-by-frame digital breakdown and a tailored block of corrective drills to take to your regular training.
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Our training camps take the team to world-class endurance destinations like Mallorca. You will stay in stunning, hand-picked luxury villas, share the road with pro triathletes, and bank high-quality cycling and running volume under expert guidance. It is the ultimate mix of serious training and an incredible social experience.
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If you prefer to handle your own day-to-day training but want an expert second opinion on your roadmap, this is for you. We will deep-dive into your past race data, current weekly schedule, and physiological bottlenecks to build you an actionable, optimised season blueprint.
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Let’s map out your goals.
Book a free intro call and see if we're a good fit. No commitment — just a conversation.