Portoscuso (Sardinian: Portescusi) is a comune (municipality) in the Province of Sulcis Iglesiente in the Italian region Sardinia, located about 75 kilometres (47 mi) west of Cagliari and about 14 kilometres (9 mi) northwest of Carbonia. The languages used here are Italian and Sardinian Campidanese.
Portoscuso borders the following municipalities: Carbonia, Gonnesa, and San Giovanni Suergiu.
San Pietro Island (Italian: Isola di San Pietro, Ligurian Tabarchino: Uiza de San Pé, Sardinian: Isula 'e Sàntu Pèdru) is an island approximately seven kilometres (four nautical miles) off the South western Coast of Sardinia, Italy, facing the Sulcis peninsula. With an area of 51 square kilometres (19+3⁄4 sq mi) it is the sixth-largest island of Italy by area. The approximately 6,000 inhabitants are mostly concentrated in the fishing town of Carloforte, the only comune in the island. It is included in the province of South Sardinia. It is named after Saint Peter.
The island is connected by regular ferry service to Portovesme and Calasetta.