Okinawa Gov. Hirokazu Nakaima told Defense Minister Satoshi Morimoto in a meeting Sunday he could not accept the U.S. plan to deploy the new aircraft, which combine airplane-like wings with rotors that allow it to take off and land like a helicopter.
A crash in April killed two Marines, and another last month injured five airmen.
The Pentagon says officials will brief Japan on the two crashes, including an initial finding that the April accident was not caused by mechanical failure.
Morimoto also visited southwestern Yamaguchi prefecture, where officials also rejected the Osprey.
Okinawa bears much of the burden of hosting U.S. troops in Japan.