A municipality in the province of Cagliari, located between Villasimius and Costa Rei, Castidas features about 20 km of coastline. The particularly charming and unspoiled countryside is rich in forests of oak and juniper trees and varied fauna. The mountains located in the surroundings are ideal for hiking and biking excursions. The local economy is based on traditional activities such as grazing and agriculture, and today improved by tourism.
Several findings attest the presence of small settlements in the area since the Nuragic Ages. In the XIV century the main centre, known as Villanova of Castiadas was founded, which was included in the Giudicato (County) of Cagliari. After the conquest of lands by the Aragonese, the lands were granted to the family of the Quiterano, of Catalan origins. After the death of the last heir of this dynasty, it was proclaimed fief and was assigned to the Family of Carroz, who ruled until the abolition of feudal rights in the late XIX century. At the same time an agricultural penal colony was created and the prisoners were used to reclaim new lands from the unhealthy marshlands in the area.

Attractions:
- the Church of Saint Basilides, which is located at the centre of a large garden. It features a single nave plan with a wooden ceiling, a gable roof and a façade of great simplicity with semicircular lunette above the main entrance door;
- the Church of Saint John the Baptist, which is a modern building, also located in a garden;
- the Church of Saints Peter and Paul;
- the Church of Saint Annunziata;
- the Church of Saint Lucia;
- the Megalithic Complex of Cuili Piras, where visitors can admire about 50 stones;
- the Beach of Santa Giusta, known for the presence of a huge rock, that has the shape of a large turtle;
- the Nuragic Complex of S'Omu and S'Orcu in the plain of Saint Giusta;
- the Neolithic Domus de Janas;
- Cala Sant 'Elmo.