Lily, the team's swimmer, had been training for the event with her father.
"It was tiring but cool," she said. "We thought we all did pretty well."
Napier Central School boys Noah Freudenberg and Charlie Williams, both 9, also competed as a team.
"I found it really fun and tiring and I felt quite happy when I came through the finish chute," said Charlie. "I did some training with my dad and we went down to Ocean Spa and did a couple of laps per week. One week we did 750 metres."
"It was really tough competition," said Noah.
Haumoana School students also put in a lot of effort, with more than a third of students at the small country school competing, teacher David Barclay said
"We had 56 children doing it, which is over a third of the school. We only had one team - so there were 53 individuals that gave it a go.
"They all got stuck in and did a bit of training over the holidays, and some were really nervous before they went in the morning but after completing the whole thing by themselves it gave them a real sense of achievement."
The Hastings event even attracted kids from out of the region, with 10-year-old Upper Hutt boy Marcus Wharekawa leaving home at 4am.
"We came up to Hastings because of the triathlon but we are also going to visit our cousins," he said.
Marcus was also the lucky winner of an Avanti Black Thunder bicycle.
"I was quite surprised when I won it, but it was quite fun doing the triathlon."
Weet-Bix Senior Brand Manager Phil Irons said the Hastings event was a huge success and organisers were thrilled.
"The Sanitarium Weet-Bix Kids TRYathlon is often the first sporting event Kiwi children try in their lifetime, and we were proud to see such a large number of Hastings children enjoying the event with the support of their families, friends and school groups," he said.
