The Greeks arrived to Corfu around 750 BC, establishing a colony from the city of Eretria on the island of Evia. Corfu supplied the Eretrians with lumber for ships and became an important stepping stone to the west. In 734 BC the Eretrians were driven out by the Corinthians who brought great wealth and culture to the island. But in 664 Corfu fought with her mother city of Corinth in what Thucydides described as the first sea battle in Greek history. It was not the last battle between the two cities who were at odds over economic matters for centuries. In the late seventh century BC, Periander, tyrant of Corinth succeeded in conquering the island but this began a period of extensive building and creativity, including the construction of the temple of Artemis at Agia Theodori and cenotaph of Menecrates. The island prospered with trade and by the end of the 7th Century was minting its own coins and has a population of over 10,000 people.

During the Persian wars of the fifth century, Corfu had a fleet second only to Athens, and sent a fleet of 60 ships to the battle of Salamis.

In 431 BC it was over yet another dispute between Corfu and Corinth that led to the Peloponesian wars which was the World War of its time with all the city-states of Greece taking the side of either Athens or Sparta, when the Athenians backed Corfu and the Corinthians sided with Sparta. The island lost half its population in these wars and eventually felt to the Spartans. In 229 it was invaded and conquered by pirates from Illyria.