Coordinates: 36°0′N 3°0′W / 36°N 3°W / 36; -3

The Alboran Sea is the westernmost portion of the Mediterranean Sea, lying between Spain on the north and Morocco and Algeria on the south. The Strait of Gibraltar, which lies at the west end of the Alboran Sea, connects the Mediterranean with the Atlantic Ocean.

Its average depth is 1,461 feet (445 m) and maximum depth is 4,920 feet (1,500 m).

The International Hydrographic Organization defines the limits of the Alboran Sea as follows:

On the West. The Eastern limit of the Strait of Gibraltar [A line joining Europa Point to P. Almina (35°54′N 5°18′W / 35.9°N 5.3°W / 35.9; -5.3)].

On the East. A line joining Cape de Gata (Spain) to C. Fegalo (Africa) (35°36′N 1°12′W / 35.6°N 1.2°W / 35.6; -1.2).

Surface currents in the Alboran Sea flow eastward, bringing water from the Atlantic into Mediterranean; deeper subsurface currents flow westward, carrying saltier Mediterranean water into the Atlantic. There is typically a rotary circulation, also known as a gyre, in the Alboran Sea as a result of this exchange of water. The Alboran Sea is a transition zone between the two seas, containing a mix of Mediterranean and Atlantic species. The Alboran Sea is habitat for the largest population of bottlenose dolphins in the western Mediterranean, is home to the last population of harbour porpoises in the Mediterranean, and is the most important feeding grounds for loggerhead sea turtles in Europe. The Alboran sea also hosts important commercial fisheries, including sardines and swordfish. In 2003, the World Wildlife Fund raised concerns about the widespread drift net fishing endangering populations of dolphins, turtles, and other marine animals.