Nearly 20 kids aged under four are dying by drowning each year, as parents are urged to constantly supervise their children when they're in the backyard pool.
Royal Life Saving Australia has delivered that message while launching its campaign of what it predicts to be a busy peak swimming period.
Of 197 drowning deaths of children aged less than four in the past 10 years, 65 per cent were in a swimming pool or bathtub.
Four-in-five of the swimming pool deaths happened when the child wasn't being directly supervised by an adult.
Royal Life Saving Australia CEO Justin Scarr said his organisation's message was straightforward - "constant supervision is absolutely critical".
"Very young children are really vulnerable, particularly those crawlers or early walkers, they can be gone in a flash," he told AAP.
"Now is the time the backyard pool is being used with the weather heating up, and you've got to be so careful about those very young children who can be drawn to the pool by older children."
Social gatherings can be a real risk where kids might be in the pool as parents socialise on the outside, Mr Scarr said.
"I could hear my neighbours in the pool on Sunday, it's family and friends having some great fun but when everyone is leaving, you've got to be so careful about those toddlers who might still be inside the pool fencing," he said.
"We just encourage constant supervision, and for everyone to check their pool fencing and gate locks are working."
Of 92 swimming pool drownings suffered by children aged less than four since 2014, nine-in-10 occurred in a backyard pool.
Ensuring gates are locked and pool fencing is robust would be critical to potentially saving lives, Mr Scarr said.
Tragically, 37 children aged less than four drowned in a bathtub in the past 10 years.
More than half of those were aged less than one year.
