The Cortez round stingray, like other stingrays, has a flattened body, with expanded pectoral fins that are fused to the head and body to form a round, flat disc. However, round stingrays differ from other stingray species in having a significantly shorter tail, about equal to or slightly less than the length of the disc, and a well-developed, rounded caudal fin. No dorsal fins are present. As the name suggests, the disc of the Cortez round stingray is roughly circular in shape, with a slightly angular snout. The skin is smooth, and the upper surface of the body is brown or brownish grey in colour, with variable, irregular, relatively widely spaced dark blotches and spots. A long, venomous spine is located halfway along the upper side of the tail.

The taxonomy of this small stingray is currently being investigated, as it may form a single species with the similar bullseye round stingray, Urobatis concentricus, which in turn may be a colour morph of the round stingray, Urobatis halleri. However, the Cortez round stingray can be distinguished from Urobatis halleri by the dark blotches on its disc.