More than 300 children will take to the pool in Rotorua's Under-14 Water Polo Development Tournament this weekend.
Water Polo Rotorua president Slim Potter said it was by far the most teams the annual tournament, at the Rotorua Aquatic Centre, had hosted.
Rotorua has one boys and one girls' team entered. They will go up against teams from Auckland, Tauranga, Waikato, Wellington and Canterbury.
"We used to run the tournament with about 12 teams and now it's 25. It's so big now, the sport is growing in New Zealand, for the young ones especially.
"It's a great sport, it's good fitness and it's an alternative to swimming. Most of these kids are swimmers and water polo is a chance to try something different and play a team sport," Potter said.