The catamaran, with 21 passengers and two crew members on a 4-hour Thanksgiving morning dive outing, was returning to shore when it was struck by what witnesses called a rogue wave in the Atlantic Ocean, the South Florida Sun Sentinel reported Friday.
Pompano Beach fire-and-rescue crews were dispatched to Hillsboro Inlet and found the boat, named the Coral Princess, "in pieces, upside down in the water," said agency spokeswoman Sandra King.
Lifeguards from the Pompano Beach ocean rescue unit arrived on pedal-powered boats and pulled passengers to safety, the newspaper said.
One woman, identified as Nina Poppelsdorf, 54, was unconscious when she was pulled from the water. She was pronounced dead at a local hospital, said Broward County Sheriff's Office spokeswoman Dani Moschella.
U.S. Coast Guard officials said in a release Thursday they hadn't determined the cause of the accident Thursday, which was under investigation.