The incident occurred at a beach area in Duong Dong Ward, where a group of tourists was bathing amid bad weather and strong waves.
Rescue workers used amphibious motorbikes to bring the victims ashore, while medical staff from nearby hotels carried out emergency first aid at the scene.
One male tourist, believed to be around 20 years old, died despite rescue efforts. Two other tourists were taken to the Phu Quoc Medical Centre for further treatment and monitoring.
Authorities said Phu Quoc had experienced rough weather, strong winds and high waves in recent days.
Local officials said warnings had repeatedly been issued to tourism businesses and visitors about sea safety and avoiding swimming during bad weather, but accidents continued to occur.