Meanwhile Steve also joined the family in the sport for the past couple of years, although the 49-year-old admits he faced a steep learning curve.
"I couldn't really swim up until 18 months ago but life is about challenges," he says.
While Cheryl has competed in several IRONMAN 70.3 races and in two full IRONMAN triathlons, Steve and Bryce, a Massey University student, are competing in only their second IRONMAN 70.3 event and Darren, a final year student at Palmerston North Boys High School, makes his debut over the distance.
The big question is who will prevail on the day?
"We'll all be watching over our shoulders and there will be a few family side bets," says Cheryl. "I'm looking for a 5:20 time and Steve is just looking to try and beat me. Darren is looking for five hours and Bryce a 4:30."
The family, who often train together and who competed in their respective age groups at the World Triathlon Championships in Mexico in September, fully appreciate the time they spend together pursuing their shared passion.
"Some people take their kids to Disneyland but we compete in triathlon," says Steve. "It is just what we do."
More than 1200 competitors from over 30 nations will take part.