Images taken by a remote-controlled vehicle from the ship showed parts of the plane's wing and words on the fuselage, Singapore Defense Minister Ng Eng Hen said on his Facebook page. He said Indonesian search officials have been notified so they can begin recovery operations.
The fuselage section that was found is 30 meters long and 10 meters wide with a height of 3 meters, Indonesia's National Search and Rescue Agency chief Henry Bambang Soelistyo said.
"The fuselage with a wing still attached on it was found in the priority search area and has been confirmed as part of AirAsia plane," Soelistyo said.
He added it was almost two miles from the tail, which was found earlier, and 2,625 feet from the black boxes, at a depth of 92 feet.
The plane carrying 162 people disappeared from radar on Dec. 28 less than halfway into a two-hour flight from Surabaya, Indonesia, to Singapore.
Many of the victims are believed to be entombed in the main section of the aircraft's cabin.
Also Wednesday, fishermen found two bodies along with plane seats and debris off the coast off South Kalimantan, bringing to 50 the total of bodies recovered so far.
President Joko Widodo expressed happiness for the discovery, saying that divers would examine the fuselage Thursday.
The plane's "black boxes" — the flight data recorder and cockpit flight recorder — were retrieved on Monday and Tuesday and will be key to learning what caused the plane to crash. Bad weather is a suspected factor.