The island’s history dates from the 10^th to 5^th century BC and its inhabitants were Pelasgi, Kares, Durians and Phoenicians, who lived on the island at different periods. The island was divided into 30 municipalities and during the early stage of the Peloponnesian War 412 BC the island formed an alliance with the island of Rhodes. In the ancient times the island fed 7000 people and cultivated two crops of wheat every year in small fields. On Halki there was copper which , according to historians, accounts for its name Halki-(copper in Greek is halkos).

In later centuries the island was occupied by imperial powers, mainly the Arabs in the 7^th century AC and then the Venetians in 1204. In the 14^th century the Knights of Rhodes granted the island of Halki to the Assanti Family. This family built a castle on the ruins of a fortressed acropolis. Classical and Hellenistic walls have also been discovered. The pirates during the medieval times forced the people to move up the mountain , far from the sea, to live. They went to Horio. After many years, when the fear of the pirates was eliminated, the people started building their houses down in the amphitheatre of Emborio, leaving their houses on the mountain to fall into pieces.

During the Turkish occupation in the mid 19^th century the island became rich and reached the goldeb age of prosperity. Other islands of the Dodecanese complex such as Symi, Kalymnos and Kastellorizo developed a high level of intellect and economy. During the Italian occupation many privileged rights were removed from the island and trade and sponge fishing were badly affected and the population started emigrating, the largest volume of it was in 1911-12, who went to tarpon Springs, Florida, where sponge fishing continued to flourish.During the Italian occupation, Halki had its Post office and the Police station due to the Italian building programme. Italian schooling was compulsory and most of the inhabitants became bilingual. Halki’s intergration with the rest of Greece took place in 1948.

The population of Halki began to diminish and from 3000 people , it fell to around 200 and the beautiful houses of Emborio fell into ruin , too.The Greeks from Halki, never forgot their roots and from the countries they emigrated to, sent money to restore buildings and to construct roads.The population of Halki today counts only 250 residents, who work with tourism, which is beginning to develop with the proper infrastructure and the island is now known as the centre of peace and friendship.