She said Life Education Trust Rotorua saw 6000 children a year, which was a big commitment and they had to find the funds to keep running it.
Dunker Julie Voss, who took part in a submarine costume, said she had been nervous beforehand because she could hardly see.
She said it was a lot colder than she was expecting in the water.
"It was great fun."
She said Life Education Trust Rotorua was a great cause to get behind because it supported children and went to all schools, teaching them about who they were, being healthy and being confident.