Dolabella auricularia is a rather large species. It can reach a length of 40 cm. It can be recognized by a flattened disk on the posterior surface of the animal. This species can be found with soft pustules, leading to a rather knob-like appearance. It has a short, blunt head. Its body is covered with tubercles and skin flaps. The inner shell has a typical earlike form. It gives off purple ink when disturbed. The penis is unarmed.

This sea hare lives in areas that are sheltered from rough currents. They will often hide in seagrass sand and mud, feeding on algae. Intertidal rock pools are also a favoured place to live.

Dolabella auricularia is sometimes used by keepers of large marine aquaria, to keep algal growths in the tank down, because the sea hare feeds on them.