I'd at least be willing to bet that there has to be at least one Legion that left to explore the world beyond the Three Great Continents, and they'll provide us a means to travel to one of the other major landmasses in the world. Considering their technological superiority, I can't imagine the Garleans wouldn't have sent at least one group to fly across the oceans, in the name of following the footsteps of the Allagans or something.