Skiathos  is a small Greek island in the northwest Aegean Sea. Skiathos is the westernmost island in the Northern Sporades group, east of the Pelion peninsula in Magnesia on the mainland, and west of the island of Skopelos.

The island has a northeastern to southwestern direction and is about 12 km long and 6 km wide on average. The coastline is indented with up to 65 sandy beaches, inlets, capes and peninsulas. The southeast and southwest parts have gentler slopes and that is where most of the sandy beaches, settlements and facilities are located. The terrain is hilly but more rugged on the north coast, with the highest peak at 433 m. There is a communications tower on this peak.

The main town is the Town of Skiathos (pop. 4,988 in 2001) and along with the airport are located to the northeast next to a lagoon. Other settlements along the coastline are Χanemos (195), Kalyvia (179), Troulos (159), and Koukounaries (126).

The Municipality of Skíathos includes the islets of Tsougria, Tsougriaki, Maragos, Arkos, Troulonisi and Aspronisi. They are scattered a few kilometres off the southeast coastline and are clearly visible from the town and the beaches. The larger island of Skopelos is visible from Skiathos with the more distant islands of Euboea and Skyros visible under very clear weather conditions. Total land area of Skiathos is 50 km².

Town of Skiathos:

The main paved road runs all along the southeastern stretch of the island with several narrow dirt roads branching off towards the interior and the northern coast. Farmland exists around all the major settlements on the island.

Despite its small size, Skiathos with its many beaches and wooded landscape is a popular tourist destination. It has over 60, mostly sandy beaches scattered all around the 44 km coastline. Some of these are Trulos, Vromolimnos, Koukounaries, Asselinos, Megali Ammos and Mandraki.