Danielle Harlick, 11, said she knew what to expect after completing the TRYathalon last year.
"I'm doing it again this year because I like to push myself and want to get a better time this year. I have started training and go for runs around my street and go swimming at the aquatic centre."
Keighley McKenzie, 10, said it was her first time taking part.
"Both my brother and sister have done it before so they told me what it is like. My mum has been helping me train and I am going to do the swim, bike, and run by myself."
Adams has attended TRYathlon events in previous years, and said she was thrilled to make her support of the 2014-2015 series official.
"I was really sporty growing up and saw the benefits, so I'm an advocate for getting kids active at a young age. With childhood obesity on the rise it is even more important that we work together to get our kids outdoors and involved in activities that boost their fitness levels and their self-esteem.
"The TRYathlon provides a fun and rewarding environment for kids to give sport a try and it's great to be involved."
There are 14 events in New Zealand running from December until April, and kids can enter the TRYathlon as individuals or in a team of two.
• Registrations can be completed online at http://tryathlon.weetbix.co.nz/ or by calling 09 531 5080.