Skiathos is a small island in Greece, in the Aegean Sea, the westernmost of the islands of the Northern Sporades archipelago. Resort. Most of the island is covered with forest. The coastline is 44 km long. The climate is Mediterranean, mild, dry, with about 300 sunny days a year.

The island is home to Alexandros Papadiamantis International Airport.

The name of the island of Skiathos was derived from the Greek words skia and athos ("shadow of Athos").