The Balamb Region consists of the island containing Balamb and Balamb Garden, as well as the westernmost island to the south. Oddly, the smaller islands east of the main island are part of the Trabia Region.
You won't really have free reign to leave this region (except for plot reasons) until Balamb Garden becomes mobile, at which point you can travel to most of the world.
You won't really have free reign to leave this region (except for plot reasons) until Balamb Garden becomes mobile, at which point you can travel to most of the world.