The carrier's history and fate after Germany's surrender was unclear for decades after the war. However, the Soviets decided to repair the damaged ship. It was re-floated in March 1946. The last known photo of the carrier shows it leaving Swinemünde on April 7, 1947
For many years after this there was no information about the ship's fate. There was some speculation that it was very unlikely that the hull made it to Leningrad, as it was argued that the arrival of such a large and unusual vessel would have been noticed by Western intelligence services. This seemed to imply that the hull was lost at sea during transfer between Swinemünde and Leningrad.
One account concluded that it struck a mine north of Rügen on August 15, 1947, but Rügen, west of Swinemünde, is not on the sailing route to Leningrad. Further north, in the Gulf of Finland, a heavily-mined area difficult for Western observers to monitor, seemed more likely.
On July 12, 2006 RV St. Barbara, a ship belonging to the Polish oil company Petrobaltic found a 265 m long wreck close to the port of Leba which they thought was most likely Graf Zeppelin.
On July 26, 2006 the crew of the Polish Navy's survey ship ORP Arctowski commenced penetration of the wreckage to confirm its identity, and the following day the Polish Navy confirmed that the wreckage was indeed that of Graf Zeppelin.
She rests at more than 86–87 meters (264 feet) below the surface.
"The sunken aircraft-carrier Graf Zeppelin is Russia’s property," the Defense Ministry of Germany states.
"Berlin will not claim any rights in connection with the decommissioned WWII vessel," Germany’s news agency DDP reports with reference to the military that Germany will not claim its right to the vessel’s hull.
Source - Internet