Costa Ártabra, or Golfo Ártabro, is a coastal area of Galicia, Spain. It is comprised between the costa da Morte and the Rías Altas; it has a maximum width of 5,800 metres, and a depth of 5,600 metres corresponding to the mouth of the River Mero at Santa Cristina beach. Other rivers which have their mouth in the gulf include Mendo and Mandeo. The Romans knew it as Portus Magnus Artaborum and amongst other historical references it is worth mentioning Pomponius Mela, a Roman historian who wrote in the year AD 43.
Costa Ártabra also the name of a nature reserve, a "Special Area of Conservation". This is one of the areas in which the rare Kerry Slug is known to occur.