The history of Fourni begins from ancient times, yet there is small evidence from that time. The island was known by the name Korsaioi islands and according to the historians, it was first inhabited in the 1st century BC from the Korsets. Archeological findings prove that the island had been inhabited during the Hellenistic times.
These findings include the sarcophagus that was found south of the church of Agios Nikolaos in 1927 and today decorates the square of the village. Also, marble columns of Dorian order have been found in the area of Kamari and lastly remains of a temple of Poseidon has been excavated in Chrysomilia. Throughout the Byzantine Times and the Turkish domination, Fourni was deserted as it became the pirate base of operations. According to some urban legends, many pirates have hidden their treasures in several spots of the island and secluded caves.
In the 19th century, piracy was confronted by the Greek Navy and people could again inhabit the remote islands of the Aegean. Therefore, by the end of the 19th century, the island had been inhabited again. During World War II, Fourni fell under Italian occupation. At that time, many people fled with boats to Cyprus and Egypt.
In the 1950s and 1960s, most parts of the local population migrated to large towns in Greece or abroad in search of a better life. Today, the island has about 1,500 permanent residents. The main occupation of the locals is tourism and fishing and in fact, they have one of the best fishing fleets in Greece. The history of Fournoi has been marked by many events throughout the ages.