Koufonisi (Greek: Κουφονήσι, known as Leuce in antiquity) is an uninhabited Greek islet, located 5.6 km (3 nautical miles) south of cape Goudero on the coast of Lasithi, eastern Crete, in the Libyan Sea. The island is roughly 6 kilometres (4 miles) long and 5.5 kilometres (3.4 miles) across. It has an entire surface area of 5.25 square kilometres (2.03 sq mi). It forms a close group of islands with Makroulo, Marmaro, Strongyli, and Trachilos. During the summer, the island is visited by tour boats from the port of Makry Gialos approximately 18 km (11 miles) away.