Two of the five have been recovered, and teams from the U.S. and Japan are working on retrieving the others, the Air Force said.
Of the eight crew aboard the plane, one was found shortly after the crash and confirmed dead. The Air Force has named him as Staff Sgt. Jacob M. Galliher, 24, from Pittsfield, Mass.
The identities of the other crew members haven't been released.
The crash of the tilt-rotor Osprey on Nov. 29 is one of the deadliest in the aircraft's history. A crash in Australia in August killed three Marines and two crashes last year killed a further eight Marines.