28-year-old Krystian Mielnik drowned after the car in which he was a passenger left a cross-river ferry and entered the water.
The ferry was travelling between Glenbrook near Passage West and Carrigaloe near Cobh on 9 March last.
Mr Mielnik's body was never recovered.
Another Polish man, Sebastian Loniawski, was rescued.
Divers from the Naval Service located the Volkswagen Polo car during an exercise in the area at around 10.30am this morning.
The car is lodged in mud, 40 metres out on the channel from the Cobh side.
An operation is now under way to lift the car to the surface and bring it to nearby docks.
Sources have indicated that the car appears to be empty.
