Percival, 45, died on Sunday following a blood clot which travelled to his lungs and caused heart attacks.

He enjoyed a stellar long distance triathlon career over the past decade. Percival finished the gruelling Hawaii Ironman (3.8km swim, 180km ride, 42.2km run) four times, and had finished 16 of the iron-distance events.

During March this year he completed eight iron-distance events in eight days in the eight states and territories of Australia. In the process he raised more than $80,000 for the John Maclean Foundation - John Maclean was the first wheelchair athlete to complete the Hawaii Ironman and swim the English Channel.

During 2014, Percival finished second overall at the Ultraman World Championships in Hawaii.

Based in Melbourne, Percival played a pivotal role in the development of Ultraman Australia - a feature of the local endurance calendar at Noosa Heads during May for the past two years.

"The Ultraman Australia family is devastated at the tragic loss of a great man, amazing friend, guru, mentor, world class athlete and the Ultramate," Ultraman Australia race director Tony Horton said.

"Our heartfelt sympathy goes to Craig's wife, Lindell, his children Sam and Sienna, and his family and friends. We will be honouring Craig and his contribution to Ultraman Australia at future events. Craig will be sadly missed but never, ever forgotten - his legend lives on in all of us touched by his presence."

Hendrey Chiropractic triathlete and chiropractor Carmen Atkinson had just started her association with the much-respected coach weeks ago ahead of her Ultraman debut next year.

"Just a couple of short weeks ago we chatted about my own endeavours, how you would help coach me to achieve my goals. We were due to start our journey tomorrow," she posted on social media at the weekend.

"You inspired me in so many ways. You were humble in your own brilliant accomplishments. You pushed the perceived boundaries of human physicality and capacity. You used your talents, your strength, your determination to raise money for those less fortunate.

"Without ego or personal agenda you helped so many achieve their own personal pursuits.

"Next May I race in your legacy."

Legendary race and event announcer Steve King, who has been on the Coast for Ultraman Australia, said "Craig was a humble, gracious, kind, gentle, tenacious, giving, talented man who knew how fortunate he was to have the opportunities he challenged himself to and to have the unconditional support of his loving family.

"The fact that he did so much to support others in their goals, raise funds and awareness for a good cause and, even as he has moved on, to donate that which he can to someone else so they may continue their journey, speaks volumes. It was truly an honour to know you and spend time with you on and off the course my friend."