A man swimming in the Bondi Icebergs swimming pool at Bondi Beach, Sydney

A man swimming in the Bondi Icebergs swimming pool at Bondi Beach, Sydney in September 2017

Couple swimming at the pool in Clovelly on the coastal walk in Sydney, NSW

Couple swimming at the pool in Clovelly on the coastal walk in Sydney, NSW in January 2015

Man swimming in the pool at Clovelly on the coastal walk in Sydney, NSW

Man swimming in the pool at Clovelly on the coastal walk in Sydney, NSW in January 2015

People relaxing in the water on the coastal walk in Sydney, NSW

People relaxing in the water on the coastal walk in Sydney, NSW in January 2015

Photograph of a striking Malaysian athlete seen in Kuala Lumpur, Malaysia. Pandelela Rinong. She was a diver competing for Malaysia at the ASEAN games

Photograph of a striking Malaysian athlete seen in Kuala Lumpur, Malaysia in August 2017. Pandelela Rinong. She was a diver competing for Malaysia at the ASEAN games

Woman with her wet dog coming from a swim in the Murray River in Albury, NSW

Woman with her wet dog coming from a swim in the Murray River in Albury, NSW in September 2018

Paddleboarders at Coogee Beach, Sydney

Paddleboarders at Coogee Beach, Sydney in January 2015

Surf lifesavers practising at Coogee Beach, Sydney

Surf lifesavers practising at Coogee Beach, Sydney in January 2015

Parents helping their children learn to swim at Coogee Beach, Sydney

Parents helping their children learn to swim at Coogee Beach, Sydney in January 2015

Woman in a bikini in the surf at Coogee Beach, Sydney

Woman in a bikini in the surf at Coogee Beach, Sydney in January 2015

Tourists snorkelling alongside speed boats at Phuket, Thailand

Tourists snorkelling alongside speed boats at Phuket, Thailand in August 2017

Swimming at the rock pool at Coogee Beach, Sydney

Swimming at the rock pool at Coogee Beach, Sydney in January 2015

Swimmers in the swimming pool at Bondi Beach, Sydney

Swimmers in the swimming pool at Bondi Beach, Sydney in September 2017

People in the ocean at sunrise at Hua Hin, Thailand

People in the ocean at sunrise at Hua Hin, Thailand in August 2017

Asian woman relaxing in the surf at Similan Island no 4, Ko Miang (เกาะเมียง) in Phang Na Province, Thailand

Asian woman relaxing in the surf at Similan Island no 4, Ko Miang (เกาะเมียง) in Phang Na Province, Thailand in May 2016

People swimming and surfing at Karon Beach, Phuket, Thailand

People swimming and surfing at Karon Beach, Phuket, Thailand in August 2017

Chinese tourists with an inflatable device swimming in the swimming pool at Metadee Resort in Phuket, Thailand

Chinese tourists with an inflatable device swimming in the swimming pool at Metadee Resort in Phuket, Thailand in August 2017

Inflatable lilos for use in swimming pools for sale in Phuket, Thailand

Inflatable lilos for use in swimming pools for sale in Phuket, Thailand in August 2017

People swimming back to the boat to Morakot cave on Ko Muk Island in Trang district, Thailand

People swimming back to the boat to Morakot cave on Ko Muk Island in Trang district, Thailand in May 2016

People swimming from the boat to Morakot cave on Ko Muk Island in Trang district, Thailand

People swimming from the boat to Morakot cave on Ko Muk Island in Trang district, Thailand in May 2016