The Gulf of Asinara is a sea sector included between the Asinara Island, Cape Falcone and the town of Castelsardo, in northern Sardinia, Italy. The communes facing its coast include also Stintino, Porto Torres, Sassari, Sorso, Valledoria and Badesi.
The littoral features several beaches, some kilometers long, such as La Pelosa, le Saline Ezzi Mannu and Fiume Santo, those near Porto Torres, Platamona, the beaches of Castelsardo, Valledoria, Badesi, Trinità d'Agultu, Vignola and Isola Rossa.
Porto Torres (Sassarese: Posthudorra; Sardinian: Portu Turre) is a comune (municipality) and a city of the Metropolitan City of Sassari in north-west of Sardinia, Italy. Founded during the 1st century BC as Colonia Iulia Turris Libisonis, it was the first Roman colony of the entire island. It is situated on the coast at about 25 kilometres (16 mi) east of Falcone Cape and in the center of the Gulf of Asinara. The port of Porto Torres is the second biggest seaport of the island, followed by the port of Olbia. The town is very close to the main city of Sassari, where the local university takes office.
Castelsardo (Sassarese: Castheddu; Castellanese: Calteddu; Sardinian: Casteddu Sardu) is a town and comune in Sardinia, Italy, located in the northwest of the island within the Metropolitan City of Sassari, at the east end of the Gulf of Asinara. It is one of I Borghi più belli d'Italia ("The most beautiful villages of Italy").
Valledoria (Gallurese: Codaruìna; Sardinian: Codaruìna; Sassarese: Codaruìna) is a town and comune in the Metropolitan City of Sassari situated at the center of the Gulf of Asinara, near the mouth of the Coghinas river.