Emergency services were called after a speed boat went missing on the Clyde River on Saturday night.
Marine Rescue Batemans Bay received a call from police about 9.30pm, asking for help to locate the missing boat.
The adult and three teenagers on board had gone up the river at 8pm but did not return before dark.
A Marine Rescue spokesman said Marine Rescue Batemans Bay put its Magnum 20 on the water, with unit Commander Mick Syrek and skipper Glenn Sullivan on board, as well as a police officer, to search for the vessel.
Marine Rescue also tasked Snowy Hydro SouthCare helicopter to assist.
"About 11.20pm the helicopter located the vessel on the Clyde River, 16km by river north of the Nelligen Bridge," the spokesman said.
"The helicopter reported there were occupants on board and directed Marine Rescue to the vessel.
"They got there a few minutes before midnight and took all the occupants of the vessel on aboard.
"They were all okay but they were cold and suffering from mild hypothermia."