Salmagi is a small townland within the hinterland of the commune of Quartu Sant'Elena in Sardinia, Italy.

Salmagi is currently a residential area, while high in the mountains, goats are managed by a shepherd.

To the west, along the coast, is the Port of Capitana (Marina di Capitana) and further west is Cagliari, the main city of Sardinia and the small granite peninsula of "Is Mortorius",[1] "The Prohibition of Activity".

East of Salmagi is "Terra Mala", "Bad Land" and a cliff-face coastline until Villasimius.

The coastland at S'Arpagiu is Spiaggia Tonnara "The Beach of the Tunnery" where a Tuna fish factory once operated.