Inis Mor is a very small island and the other two Aran Islands are even smaller. Inis Mor is about 8km in length and at its widest point is 2km wide. The narrowest point is 500 meters wide. There are 800 people living on Inis Mor. It is possible to travel the whole island in one day.
The other two Aran Islands are even smaller. You can get around them by walking in half a day each. They are very small in comparrison.
Between the Islands there are about 500 meters of water. So the islands are very close together with narrow channels seperating them.