The US Air Force plans to deploy 10 to a base on the outskirts of Tokyo by 2021.
The Japan's Self-Defense Forces also plan to use 17 to create an amphibious rapid deployment unit.
But the aircraft have been involved in a series of deadly accidents outside Japan in recent years, including in May of last year when an Osprey burst into flames after a crash in Hawaii. Two marines were killed and 20 others were injured.