The island of Mljet is one of the Southern Dalmatia islands. It stretches parallel along the eastern half of the Pelješac peninsula, separated from Mljet by the 8 km wide Mljet Canal. The NW part of the island (the Goli cape) is located 18 kilometers from Korčula, and the Gruj cape on the SE end of the island is located 30 kilometers from Dubrovnik. Mljet has an overall length of 37 km with the average width of 3 km and a total surface area of 100.4 km2. The highest peak on the island is Veliki Grad with an altitude of 514 meters a.s.l. and it is located in the centre of the island, above Babino Polje.

The characteristics of the Mediterranean climate are apparent at Mljet, with its dry, sunny and very warm summers, and rainy but mild winters, with a majority of rainfall coming near the end of fall and in the start of winter. It is an island of lush Mediterranean vegetation, clear and clean sea, picturesque bays and rich sea life. People who visit this historical and beautiful island characterized by pure nature fall in love with it and often return. Due to its specific geographic location and soil structure, Mljet has lush vegetation mostly consisting of the Aleppo pine (around the Veliko and Malo jezero, the village of Goveđari, the bay of Pomena, the hills of Bugari and Gaja, the bay and field of Sutmihalj) and the holly oak, with particulary well preserved forests at the locations of Valakija, Planjak, Kneže polje, Ivanje polje and Nikin dolac. There are also anthropogenically degraded forms of vegetation such as shrubland, garrigue and rocky grounds. The animals of the island are beech marten, Herman’s tortoise, fat dormouse, East-European hedgehog, numerous birds such as the European honey buzzard, the European shag and the tawny owl, invasive species such as the small Asian mongoose and boars, and several types of snakes and lizards.

Mljet has mostly managed to preserve its natural origins and authenticity thanks to its geographical location and the fact that it is separated from land. Sea, strong waves, sea currents and wind formed the structure of the Mljet coast as we know it today – filled with bays, caves, steep coves and rocks. The island was formed by rising from the sea, so it only forms part of the land from which it is separated. The sea around the coast of Mljet is warmer and saltier than it is in the north of the Adriatic. During winter, sea is colder only in bays stretching deeper in the land and in the lakes of Mljet. During summer, the sea is warm enough to swim in it, and its temperature is 2-3 °C higher along the coast, in the bays and especially in the lakes of Mljet than it is on the open sea. During intense summer heats, due to lush vegetation and clean air, even the hottest days are enjoyable. The benefits of the sea and vegetation can be felt all over the island. There are several freshwater springs on Mljet, as well as pools of brackish water, called ‘blatine’, which were introduced into the Natura 2000 network and thus recognized as an important habitat on European level.