Okinawa offers a distinct driving experience. Unlike the United States, people drive on the left side of the road. The slow lane is on the left, and the fast lane is on the right, although there usually isn't a significant difference between either. All speed limits are marked in kilometers per hour and, except for the Okinawa Expressway, there is no authorized speed zone beyond 60 kilometers per hour, or about 37 mph. In addition, all traffic signs here conform to international standards. Many roads are much narrower than standard American roads, traffic congestion is more the rule than the exception, and coral dust-laden roads are slick when it rains. Defensive driving is an absolute necessity. Drinking and driving and illegal drugs are dealt with very severely by both Japanese and Military authorities.
To become a licensed driver in Okinawa, you will need to obtain a SOFA license. SOFA is an acronym for Status Of Forces Agreement. It is an agreement between Japan and the United States military forces in Japan that allows military dependents to move freely in the country and enjoy many of the privileges of native residents. You'll learn more about SOFA status upon your arrival. But be prepared you'll also need to take a written driving test. You'll find study materials here.