The Coast Guard on Saturday said it was still searching for three passengers, including an adult and two children, after a boat capsized on the St. Johns River in Jacksonville, Florida, near Goat Island, leaving one person dead.

Around 7 p.m. Friday, Coast Guard Sector Jacksonville received an alert of a capsized 18-foot vessel with four people atop the overturned boat and four others trapped underneath. 

The four people on top of the boat were rescued. None of the passengers were wearing life jackets, the Coast Guard said. 

US COAST GUARD RESCUES 3 AFTER BOAT CAPSIZES OFF FLORIDA COAST: VIDEO

The Coast Guard launched a rescue boat and helicopter crew, and the Jacksonville Sheriff’s Office, the Jacksonville Fire and Rescue Department and the Florida Fish and Wildlife Conservation Commission assisted in the search. 

“The four people on top of the vessel were rescued by a Jacksonville Sheriff’s Office marine unit, and one person was recovered from the water unresponsive,” the agency said in a news release Saturday. “A Coast Guard Station Mayport rescue surface swimmer attempted to contact the people reportedly underneath the vessel but received no responses. 

“Divers from the Jacksonville Sheriff’s Office searched underneath the vessel but did not locate any people.” 

YACHT EXPERT BREAKS DOWN LUXURY SUPERYACHT TRAGEDY AFTER BOAT CAPSIZES IN FREAK STORM: ‘ALWAYS LIMITS’

A Coast Guard member searches the St. Johns River Saturday for three missing boaters after their boat overturned in Jacksonville, Fla. (U.S. Coast Guard)

“At this point, we have found one person from the missing, and they are deceased,” Jacksonville Fire Rescue Department Capt. Eric Prosswimmer told reporters late Friday. “It’s a really unfortunate situation, and our hearts go out to all the family members.”

Officials haven’t release the age of the person who died. 

A Coast Guard boat searches the St. Johns River in Jacksonville, Fla.  (U.S. Coast Guard)

CLICK HERE TO GET THE FOX NEWS APP

The cause of the capsizing is under investigation. 

Fox News Digital has reached out to the Jacksonville Fire Rescue Department.