There are 13 teams in the girls' tournament and 12 in the boys' tournament. They will be split into pools and play a round robin between 11am-9pm today and 7.30am-8pm tomorrow, before playing semifinals and finals on Sunday.
Last year the Rotorua boys' team finished third, while the girls' team did not make the semifinals.
"We've got a good boys' squad this year, they should be fairly strong.
"Our girls are very young - there are quite a few 10 and 11-year-olds in there. Whereas, most of the big clubs' players are 13 and 14.
"It's a great experience for these young girls though, most played under-12s earlier in the year and enjoyed it."
Last year Auckland's Marist Knights won the boys' tournament and Tauranga Blue won the girls'.
Water Polo Rotorua has been running flippa ball for the last five years, which allows players to learn basic water polo skills in a shallow pool with their feet on the ground.
It is aimed at getting children involved in the sport and has been a major factor in the growth the sport experiences today.
"The numbers vary a bit, but on a Tuesday night we have about 500 kids down here playing. Just about every school is involved, there's 35-40 teams."
The challenge now is retaining players as they get older.
"When they get to 16 and 17 they get girlfriends and boyfriends, and jobs in some cases. It gets a bit tougher at that age and when they go to university, but at this under-14 age the numbers are everywhere," he said.
