The 47-year-old woman was swimming at Gordons Bay near Clovelly around 1.40pm when she reportedly suffered a medical episode in the water, NSW Police said.
Surf Life Saving said three young women had found the woman floating face down and pulled her out of the water and started CPR.
But despite the best efforts from the public and paramedics to revive her by conducting CPR for more than 30 minutes, she died at the scene.
“Three young girls pulled her in, no more than 15 years old, and they did a fantastic job under the circumstances,” Surf Life Saving’s Ben Hennan said.
A report will be prepared for the coroner.
It is the second drowning in New South Wales today after a 62-year-old male surfer was pulled unresponsive from the water at Jervis Bay on the state’s South Coast.
Surfers, swimmers and paramedics tried to revive the man but he also died at the scene.
Surf Life Saving said there have been eight coastal drownings since the start of summer.
”Last year across the state, the period between December 2021 and February 2022 claimed the record for the most coastal and ocean drowning deaths over a summer, with 25 fatalities recorded in NSW, despite the higher than usual rainfall from La Niña and reduced beach attendances,” the authority said.