The North West Police Underwater Search and Marine Unit was called to the scene at around 9.15am this morning (February 3).
The specialist underwater search team parked its purpose-built truck at Homebase car park, where a rigid inflatable police boat was unloaded and launched into the water off Mariner's Way.
Exhausted police divers could be seen emerging from the water after searching the depths for around two and a half hours.
Police divers with the underwater search unit emerge from Preston Docks where they have been searching for a missing person
Lancashire Police said the operation is "part of a search for a missing person".
The force has been approached for an update on the search.
The police underwater search team were called to Preston Docks to help search for a missing person The underwater search team prepare to send divers into the freezing waters of Preston Docks The underwater search unit were called to Preston Docks shortly after 9am (February 3) to help with the search of a missing person Divers entered the water at Preston Docks after police officers found a car located at the docks which is believed to belong to a missing person