The origins of life in Skiathos are lost in the misty background of mythology. According to the available historical evidence, the island's first inhabitants were Pelasgians, who were followed by Cretans, Thessalians (in the Mycenaean period) and Chalcidians. Herodotus mentions Skiathos as the only island of the Northern Sporades that took part in the Persians Wars.

On the reef called Myrminx or Lefteris, in the narrows between the west coast of Skiathos and the east coast of Pelion, one can see the remains of a stone column. It has been conjectured that this may have been a memorial put up by the Persians to commemorate an engagement between three Greek ships and ten of their own. Another school of thoughts holds that it was some kind of seamark, possibly even a lighthouse, built by Xerxes' expeditionary force. If the second theory is correct, it makes this the oldest seamark in the world, since it predates the Pharos at Alexandria by about two hundred years.

In 476 B.C. Kimon enlisted Skiathos in the first Athenian Confederacy. In 403 B.C. it was captured by the Spartans, only to be retaken by the Athenians in 394 B.C. and brought into the second Athenian Confederacy.

The whole island seems to have had a friendly relationship with Athens, because later in the 4th century we find it mentioned as one of the Athenians' naval out posts against the threatening presence of Philip II of Makedonia. Eventually, however, it fell to the Macedonians, and then in the middle of the 2nd century B.C. it was captured by the Romans under Septimius Severus. Under the Byzantine Empire (A.D. 330-1207) Skiathos was left to languish in poverty, a small, obscure, out-of-the-way island. We can tell that Christianity took root and flourished there, however, because it was an Episcopal see as early as the 4th century.

In 1207 it shared the fate of the rest of the Northern Sporades and came under the way of the Ghizzi, a Venetian family whose rule lasted until 1276. It was then won back by Byzantium and remained in the Byzantine Empire until the fall of Constantinople in 1453. During this period it suffered heavily from pirate raids, which eventually (in the mid-14th century) forced the inhabitants to abandon the old town and built a new one, now known as Kastro, on a precipitous rocky headland at the northernmost tip of the island. The remains of this medieval town are still visible today: streets, houses and churches, all in ruins. The 17th century Church of the Nativity is still in good condition and has a number of fine icons.

After the fall of Constantinople the island was ruled by the Venetians until 1538, when it was sacked by Chayreddin Barbarossa and brought into the Ottoman Empire. Throughout the centuries of thralldom and running war that followed, culminating in the 1821 War of Independence, the people of Skiathos rendered sterling service to the freedom fighters. Here a safe refuge was always available for combatants gleeing from the Turkish oppressor, and many Greek sea-captains (among them Vlachavas, Nikotsaras, Stathas and Tselios) used the island as a base. After the liberation the Northern Sporades were officially incorporated in the independent Greek state in 1830, under these circumstances, the inhabitants abandoned Kastro and rebuilt the town on its original site, where it is today.

In recent years Skiathos has developed into an international tourist resort, but it has not lost any of its old charm or dazzling purity. It is still what it was: a jewel of an island set in the aquamarine sea, within sight of far-farmed Pelion; an enchanted corner of Greece mantled with olive-trees, pines, amaranths and thyme; a microcosm of nature’ s majesty, its hillsides dotted with monasteries and chapels, obvious symbols of the islander’s God-fearing piety and spiritual feeling.