Man drowns while swimming at Wattamolla Lagoon on Christmas Day.

A 27-year-old man has drowned at a busy beach south of Sydney on Christmas Day.

Emergency services were called to the Wattamolla Lagoon within the Royal National Park near Sutherland about 6:45pm on Christmas Day.

The man had been pulled unconscious from the lagoon after disappearing under the water.

Several bystanders tried to perform CPR but he could not be resuscitated and died at the scene.

It is believed the man was swimming with friends.

Senior Constable Samuel Pascoe said police are investigating the circumstances surrounding the man’s death.

Police are urging people to remain vigilant around waterways, beaches and swimming pools during the festive season.

A report is being prepared for the coroner.

This post originally appeared on ABC News.