Arzachena is a town and comune (municipality) in the Province of Gallura North-East Sardinia in the northeastern part of the autonomous island region of Sardinia, the second largest island of Italy. Arzachena lies halfway between the original Costa Smeralda resort and Porto Rafael, both founded in the late 1950s. With a population of 13,456, it is the 2nd-largest commune in Gallura by population after Olbia.