Event distances for the individual race are swim 50m, cycle 4km and run 1.5km for 7-year-olds, 8-10 years is swim 75m, cycle 4km and run 1.5km and11-15 years swim 150m, cycle 8km, and run 1.5km.
There are also events for teams of two for each age group. One team member completes the swim, one team member completes the cycle and both complete the run.
Since the very first event in 1992, which boasted just 800 entrants, more than 300,000 Kiwi kids have given it a go.
The increase in children aged 7 to 15 enrolling for the event continues the trend of the TRYathlon's growing popularity with demand driving this year's entries to sell 85 per cent faster than previous years.
The Sanitarium Weet-Bix Kids TRYathlon events are running throughout New Zealand from November 25 until April 7.