Custom running, cycling and triathlon kit.
Crafted by athletes, for athletes.
Club teamwear and one-off race suits. Free design service, no minimum order.
Performance Socks
Always £10 a pair when you buy two or more.
One in the wash, one in the bag, one on your feet.
Our Story.
Welcome to iS3, a triathlon teamwear brand built from real experience, real passion, and real purpose. Born in South Wales, home to the legendary Ironman Wales, we design custom performance kit shaped by the demands of the sport and the athletes who live and breathe it.
iS3 is named after my children, Ivy and Seb. They are a daily reminder of why I do this and the example I want to set: work hard, dream big, and believe anything is possible. The “3” represents the disciplines of triathlon: swim, bike, run.
Our mission: deliver high-performance racewear that fits, lasts and performs — without the inflated price tag.
Welcome to a brand built on family values, athlete insight, and uncompromising quality.
Crafted by athletes, for athletes.
— Chris