A vast Saharan marine bay dug into a desert plateau and widely open to the ocean, from which it is separated along its entire length by a dune cord. Unique in its kind in North Africa, it is both a migration relay and a wintering and nesting area for thousands of waterbirds. Receiving no permanent fresh water supply, the tide maintains vast aquatic habitats that are shallow, over-salted, and highly productive.

The bay shows a mosaic of juxtaposed habitats: sand pits, seaweed carpets, Spartina steppes and samphire steppe. Overall, Ad-Dakhla Bay is the second best Moroccan wintering site for waterbirds. In addition, two species of terrestrial mammals, one endangered (Hyaena hyaena) and the other rare (Felix lybica), are present on the site as well as several species of cetaceans including dolphins, the pilot whale and Sousa teuszii.