The main occupation of the inhabitants today is tourism, but there are still some locals that are still involved with farming and livestock. The history of Sifno is pretty brief because it is not involved with any heroic achievements. The barren ground of the island kept away, many invaders who arrived once and again. Thus they did not disturb the peace of the locals whose lives were already difficult as it was.
Myth has it that Sifno got its name from Sifno, the son of Aniou who was a semi god, the offspring of Apollo and his bride Roious. Another myth mentions that after Hercules killed the giants he threw them on the island where they were petrified and turned into rocks (thus the so many huge rocks on the island). But all these sources are insufficient.
The first inhabitants of the island were Kares. After them the Phoenicians, the Cretans, and the Egyptians inhabited the island. In the end the Ionians inhabited it. After the Persian wars, the first Athenian alliance was formed with its headquarters being Delos, were the allies treasury was situated.
Delos influenced Sifno very much, even in matters of religion. They worshipped the God Apollo, but also the other gods of those times, as it is concluded from some coins that were found in the area.