The passenger, who officials said was 58, had been snorkelling with members of her family when a bull shark attacked her at Green Cay, according to Royal Bahamas Police Force Superintendent Chrislyn Skippings.
The woman, a mother from Pennsylvania whose name was not released, had arrived in the Bahamas on a Royal Caribbean cruise that morning, Skippings said.
While docked in Nassau, the capital of the Bahamas, the family booked an excursion with a private tour boat company to take them snorkelling at a popular spot in the area near Rose Island.
At around 2 p.m. local time, the woman was attacked by a bull shark while snorkelling. (According to the Florida Museum of Natural History, bull sharks are more likely than other species of shark to attack humans unprovoked.)
Family members saw the attack and rushed to help her. Staff members from the tour company helped pull the woman onto the boat and they raced to the nearest dock where paramedics were waiting.
Skippings said that the woman suffered bites to her “upper extremities” and had no vital signs after the attack.
The woman and her family had been sailing on Harmony of the Seas, a Royal Caribbean cruise ship that set sail from Port Canaveral, Fla., on Sunday for a seven-day tour.
After the death, the cruise company issued a statement, saying it was “providing support and assistance to the guest’s loved ones during this difficult time.”
The area where the attack happened has been cordoned off and closed indefinitely to snorkelers. The incident is under investigation, authorities said. The last recorded shark attack in the Bahamas occurred in 2018, according to the International Shark Attack File.
Shark attacks are extremely rare, with the Florida Museum of Natural History estimating that the odds of being fatally attacked by a shark are less than one in four million.
Last year there were 73 confirmed shark attack cases worldwide.
Many shark attacks are cases of mistaken identity and can happen when humans are swimming near large schools of fish or when there is poor visibility through the water. Sharks may also attack out of self-defence when they feel threatened.