Skyros belongs to the cluster of islands of the North Sporades. It is the largest of these islands on the east of Island Euboia from witch it is 18 nautical miles apart.
The island is comprised from three large mountain bodies witch are seperated from two level stretches, once being the sea. One starts from Achili and ends at Kalamitsa for a distance of 4 kilometers and a width of 2,5 kilometers. In the south region the mountain of Koxlias raises to a height of 794 meters and to the north the mountain of Olympus to 390 meters.
The northern part of the island gathers the largest part of the rural cultivations and natural vegetation while the southern part is usually used as pasture fields. The whole island occupies an area of 215 sq. kilometers , has a minimum width of 2 kilometers , a coastline length of 129,6 kilometers . At the center of the island and to the east side the city of Skiros is built amphitheatricly on the slopes of the ancient castle.
The island has two main plains , the flat land and the plain of Traxi, both on the northern side of the island. Smaller plains exist at Agalini-Aherounes and Kalikri. Recently on the flat land of Trahiou a big airport was build. Besides the main island many smaller islands exist numbering 32. All the coasts to the north and south have big sandy beaches over 10 kilometers long.