Officers were called to Corinthian Quay close to Lower Granton Road at around 10.35am.
Eyewitnesses said the vehicle appeared to be burnt out.
Coastguard teams have been drafted in to determine if anyone is within the vehicle.
Submerged van found near Edinburgh harbour
Police and coastguard crews were this morning retrieving a submerged van which was spotted in the water off Granton Harbour in Edinburgh.