"If you are diving from a boat, it's a legal requirement to display a dive flag," Adams said.
While things may not go wrong, Adams said divers should plan for things to go wrong during the dive or on the surface.
"Safe surfacing procedures, including safety stops, are an essential component in a scuba diver's skill set."
Adams said free divers and swimmers should have a float if more than 200m from shore, and if a person is going scuba diving to have a safety sausage to deploy on the surface.
"Always dive with a buddy throughout the dive," he said.
Adams said the buddy system was developed to improve diver survival across a range of situations.
Earlier this week, Water Safety New Zealand (WSNZ) reminded Kiwis to stay safe this summer as they hit the beaches, lakes and rivers this holiday season.
WSNZ chief executive Daniel Gerrard says too many New Zealanders drown.
"It is the time of year and unfortunately we do see a spike in preventable drownings. These losses are tragedies, we just have to keep educating people," he says.
"While we want everyone to enjoy the summer break, there have been five preventable drowning deaths on average over the past five summer holiday periods ... It is all about being prepared.
"We want people to get outdoors, but also ensure everyone comes home."
WSNZ's drowning statistics show the high-risk groups are: men; adults boating; young people swimming; and Asian, Māori and Pasifika people fishing.
On a per-capita basis, New Zealand's preventable fatal drowning rate is 1.62 per 100,000.
This rate has been steady for the past five years.
