"I'm not the best swimmer and it was cold, but I did it," she said after the race with a huge smile on her face.
The bike ride was the favourite part of TRYathlon as "you don't use up too much energy".
The Otumoetai Intermediate student hoped to take part in the event again next year, she said.
Weet-Bix Kids TRYathlon national ambassador Valerie Adams said it was important for athletes to inspire and support the next generation.
Adams said as a child her family had limited resources but they were still a sporty family. She and her siblings would be outside every day playing hopscotch, elastics and jump rope. Today children were stuck inside after school playing on electronic toys, she said.
Adams said it was important to inspire today's youth to get outside to live happier and healthier lives and the event gave children a boost of confidence too.
"Self-esteem for kids, or anyone for that matter, is so important and a great way to build self-esteem is to set goals and go about trying to achieve them."
Impact PR director Mark Devlin said 930 children participated in the third of 16 friendly races across the country, about 100 more than last year's race.
He expected 25,000 children to take part nationally.
Yesterday's event had a good mix of locals, holidaymakers and families who brought their children in from outside the Bay of Plenty with a number of last-minute entrants too, he said.
"The whole concept is that every kid is a winner," he said.
The race was supported by 168 local volunteers who too cheered along the children as they gave it their all, he said.