Koufonissi, known in antiquity as Lefki, is an uninhabited island in the South Cretan Sea, approximately 3.5 nautical miles south of Goudouras and 10 miles southeast of Makrigialos. It covers an area of approximately 5.25 square kilometres and is the largest island of a small group that also includes the islets of Makrouli, Strongyli, Marmaro and Trachilos. The ancient name Lefki is probably associated with the white colour of its limestone and marl formations, while the modern name is attributed to the numerous cavities and sea caves along its coast.

Although Koufonissi is uninhabited today, it preserves evidence of human activity from prehistoric to post-Byzantine times. Particularly important are the remains of the Greco-Roman settlement, the theatre, baths, water cisterns and workshops used for the production of purple dye. On the northern side of the island stands the small chapel of Saint Nicholas, the patron saint of local sailors. The remarkable concentration of antiquities has led to Koufonissi being informally described as the “Delos of Crete”.

The landscape is dry and almost steppe-like, with sand dunes, low vegetation, white and yellow rock formations, caves and small sandy beaches with turquoise waters. Its flora includes rare species whose distribution is mainly associated with the southern Mediterranean and North Africa.

Koufonissi, the surrounding islets and their coastal marine zone belong to the Natura 2000 network. They form an important area for migratory birds and support a notable colony of Eleonora’s falcons, while the surrounding sea contains reefs, marine caves and Posidonia oceanica seagrass meadows.

Access is mainly provided by seasonal excursion boats from Makrigialos when weather conditions permit. There are no facilities, drinking water or natural shade on the island, so visitors should carry everything they need and avoid disturbing its fragile natural and archaeological environment. Available boat services and any access restrictions should always be checked before visiting.