The giant devilray occurs in offshore, deep waters and, occasionally, in shallow waters (Bradai and Capapé 2001) throughout the Mediterranean Sea, in waters ranging in depth from few tens of metres to several thousands (with the exception of the northern Adriatic) and possibly in the nearby North Atlantic. Outside the Mediterranean it occurs along the coast of Africa from Morocco to Senegal, the Canary Islands, Madeira, the Azores, Portugal, and as a vagrant, off southern Ireland (Notarbartolo di Sciara 1987). However, since expert examination is needed to distinguish M. mobular from M. japanica, a species known from the tropical Atlantic (Notarbartolo di Sciara 1987), past reports of giant devilrays from the Atlantic may have been due to incorrect identification of spinetail devilrays.