Because of its rare natural habitats, fresh water springs and biodiversity, Vransko Lake and its surroundings have been declared a Nature Park in 1999. The Park limits are between Pirovac and Pakoštane. It stretches across 57 km², 30,02km² of that being the lake area itself, which stretches in direction north-west to the south-east, parallel with the sea coast, from which it is, in some places, less than a kilometre apart. The lake is unique because of its position and characteristics, not only in Croatia, but in other parts of Europe too. It is, in fact, a karst valley filled with brackish water as well as cryptodepression, which means that a portion of the lake lies below sea level.

The dominating characteristic of the park is its special Ornithological reserve, which received its title in 1983 because of its well preserved huge reed-patch in the north-western part of the lake as well for its immense biodiversity, and extraordinary scientific and ecological value. The reserve has been included in the list of Important Bird Areas in Europe and became Ramsar site in 2013.