The oldest name of the island of Kea was Hydrousa, though during the Turkish occupation the island was called Tzia. The present day name of Kea is derived from the hero whose name was Keo. He was the leader of Lokroi clan from Nafpaktos area who occupied the island during the antiquity.


In Kea, between the 7th and 6th BC there were four independent city states which were economically and culturally. There were Ioulis, Karthaia, Poiessa, Korissea.


During the Byzantine period, the occupation by the Franks and the Turkish, the island experienced a deep recession and became a base for pirates. From 1830, Kea like the rest of the Cyclades became part of the new state of Greece.


After 1922 and the defeat of the Greek army in Asia Minor, refugees of Greek origin settled on the island.