The Mon Calamari were a bipedal, amphibious species with high-domed heads, webbed hands and large, goggle-like eyes. In addition to being webbed, the Mon Calamari hand presented three suction-cup like holes on its palm, and featured five claw-tipped fingers: one opposable thumb, two long middle fingers, and two very short outer fingers. Although they were shaped like flippers, their feet could nevertheless fit into boots designed for humanoid feet. The females were distinguished from the males by their more prominent chest areas. The individuals that hailed from the colder polar extremes of their planet were noticeably less colorful than those who came from the tropical zones.

The Mon Calamari were vigorous swimmers and were capable of living underwater for long periods.

The Mon Calamari spawned many offspring. For example, Raddus‘s grandchildren numbered in the dozens. However, because not all spawns were expected to come of age, the Mon Calamari felt loss less keenly than humans, who reproduced comparatively rarely and fewer.

The Mon Calamari were known to find it offensive to sneeze loudly.