However, over half have not swum 25m in the last 12 months and close to half have never learnt water safety skills.
Water Safety New Zealand chief executive Jonty Mills said this needed to change.
"We have one of the highest preventable fatal drowning rates in the OECD. It is a national disgrace problem."
He said aquatic education needed to be more of a priority and people needed to remember the Water Safety Code.
On the positive side, the messages around lifejackets and the supervision of under-5s appear to be taking hold.
Bay of Plenty Regional Council senior maritime officer Ross Powell said Rotorua had two drownings in 2016, one of which involved a competent water-skier who was not wearing a life jacket.
"These risks are unnecessary. This season, now we've introduced a registration process for jet skis so users can be identified, the risk factor should reduce.
"Unfortunately with adrenaline sportspeople take risks. We will take action if we deem it necessary."
Mr Powell said they regularly promoted maritime safety, working closely with organisations such as Water Safety New Zealand.
He said they had done a lot of promotion on life jackets and people were becoming more aware of the job life jackets do now.
"Kids are educating their parents, which is great."
Rotorua Lakes Council sport and recreation manager Rob Pitkethley said Rotorua was fortunate to be surrounded by amazing waterways and it was a huge part of Kiwi life to swim, fish and do water sports.
"Swimming is a valuable life skill that, once learned, is never forgotten."
He said while most classes were full of children learning to swim, adult classes were also offered at Rotorua Aquatic Centre.
"We want to see more adults learning how to swim because they are the role models for our young people."
The Making a Difference programme, launched at the beginning of 2016 by Rotorua Lakes Swim School and Swim Rotorua, had been a great success, he said.
Last year alone, more than 2000 children from 20 local schools had the opportunity to learn to swim for free.
"We hope that this momentum is continued. Swimming or water activity is a large part of life for most New Zealanders and aquatic education needs to continue to be a big focus in schools and at home. One preventable drowning is too many."