All the bodies were male and were found within two miles of each other off Hollywood in Broward County, authorities said. Mark Barney, a Coast Guard spokesman, said the bodies appeared to have been in the water for "a decent amount of time."
"We don't know who they are and how they perished," said Michael Mullen, a Coast Guard officer in Miami. "They could be from a Cuban migrant venture that didn't go well. But that is only speculation."
Coast Guard planes spotted what appeared to be more bodies but a vessel searching the area could not find them.
Early Monday morning, police found 19 people, who appeared to be migrants from Haiti, on Hillsboro Beach in northern Broward County. One woman was dead, and another was hospitalized.
Police said they found no signs of a boat. They came to the beach after getting calls from residents of a nearby condominium complex.
Thousands of Cuban and Haitian immigrants try to reach Florida by boat every year. Under U.S. immigration policy, Cubans who get ashore are allowed to remain.