Is Pruinis is found on the Island of Sant'Antioco in the municipality of the same name, and is reached by going along the road that leads to the beaches out of the town of Sant'Antioco. The island is the largest of the smaller islands in Sardinia and is connected to dry land over an isthmus probably built by the Carthaginians and improved upon by the Romans. Its coasts are jagged in the south, where cliffs are found, and it is sandier in the north. The two most important towns are Calasetta – having a well equipped marina - and Sant'Antioco, which has numerous facilities. The beach of Is Pruinis is very long and has coarse sand.