Two originals are competing in the 26th Bonita Ironman New Zealand on Saturday 6 March, which is the oldest international Ironman event.
Among the field of 1252 participants from 39 countries is American Dave Orlowski who was one of the 15 starters in the first Ironman in Hawaii in 1978.
Orlowski finished third of the 12 finishers in that remarkable event on Oahu, which linked three existing endurance events on the Island – the 3.8km Roughwater Swim, the 180km Around Oahu bike race and the 42km Honolulu Marathon all into a single, continuous event.
It took until 2008 for the American to return to Ironman, competing in the 30th anniversary in Hawaii. The event has come a long way from that day in 1978 when the then 22-year-old Marine took part. There was no support provided at all, and so Orlowski came up with his own solution.
"I'll just cut off a pair of jeans and stick money in my pocket." In 1978, there was no traffic control, there were no aid stations. So Orlowski's aid stations along the bike course became gas stations and grocery stores, even a McDonalds.
Orlowski was tempted back to Hawaii in 2008 where he raised money for charity, along the way, and now is on a mission to complete every official ironman event around the world culminating in the 35th anniversary of the Ironman World Championship.
It has been a long Ironman break also for Blenheim's Michelle Gammie-Catterick.
She won the women's title in the original New Zealand race in 1978, held from Mission Bay in Auckland.
Now she is back 26 years later for just her second Ironman after leaving the sport following her initial success where she shared the podium with the men's winner Scott Molina, who went on to become a world champion and now lives in New Zealand.
"I was watching the coverage on television of last year's 25th anniversary and that brought back memories really," Gammie-Catterick said.
"You see people of every shape and size doing it and it got me motivated. I thought if they can then there's no reason why I shouldn't do it.
"I really gave the sport away after that first race. I've been a mother raising a family although we are all keen cyclists so I've been keeping as fit as I can."
She finished third in her age group at the Port of Tauranga Half Ironman and since then has "not enjoyed the big increase in training as much" although she has completed her preparations injury-free.
The oldest starter is Taupo's Neil Fleming, a five-time finisher at Ironman New Zealand, who is 73, one of five septuagenarians in the race including Tony Jackson, who with fellow Aucklander Mike Ramsay, has completed all 25 previous Ironman New Zealand events.
The youngest is Gareth Denman, 18, who is competing with his mother and her partner, travelling all the way from Llanelli in Wales.
Ironman has also been the panacea for weight loss. No more so than Auckland's Henry Tohu who has lost 40kg in his Ironman preparations or Waipukurau's Sandra Kappely who has lost 35kgs in her quest to prove that "the sky's the limit."
That is certainly true for Wellington's Mike Wilkinson who was the victim in a terrible accident two weeks before ironman New Zealand in 2005 that left him in a coma and suffering from a severe brain injury. While still battling some issues from that accident, Wilkinson is back with his focus on realising that unfilled dream.
So too is another Wellingtonian in Nick Ruane who was paralysed down one side after an accident as a child. In recent times he has lost over 40kgs to become an excellent cyclist who has his sights on the 2012 Paralympics.
And after learning to swim with one arm, Ruane wants to realise a dream to become an Ironman.
