This island of barren rock, golden beaches and tiny green valleys owes its fame to its celebrated sponge fishers. This is the main profession for men on the island, and the theme for many local dances and folk songs. Sponge-fishing means a yearly excursion to the seas off the North African coast. Sponge-fishers of Kalymnos leave with their boats every spring. Their departure is a moving and important event which is therefore accompanied by glamorous religious ceremonies. After approximately five months' hard work sponge-fishers return to the island. One feels then the relief and joy that overtake the people of Kalymnos. The whole island puts on festive dress and prepares to celebrate the return of the sea-beaten sailors.

Kalymnos is neighbored by the small island of Telendos, which was part of Kalymnos, but after a major earthquake 554 AD was split and separated from Kalymnos by a strip of water (about 800 m wide).

Between Kalymnos and Kos there is the islet of Pserimos which is inhabited and, with an area of 11 km², is one of the largest among the lesser islands of Dodecanese. Near Pserimos lies the islet of Platí, and about 5 km to the NE there is the small islet of Kalolimnos.