Arzachena (Gallurese: Alzachèna, Sardinian:Altzaghèna) is a town and comune in the province of Olbia-Tempio, northern Sardinia, Italy. Arzachena lies half way between the original Costa Smeralda resort and Porto Rafael, both founded in the late 1950s. After Olbia and Tempio Pausania, it is the third largest commune in Gallura by inhabitants.