[1][2][3] These tropical reef-associated crabs occur in coral reef, lagoons, rocky platforms, sand and seagrass beds, from littoral and subtidal zones to deep waters, at depths up to 50 m. [4] Dardanus megistos can reach a body length of about 20 cm (7.9 in).

[4] These large crabs have a bright red body with small white eyespots surrounded by black.

Their bodies are covered with long erect coarse hairs of a dark red color.

The soft, asymmetrical abdomen is spiral-shaped, useful in keeping in the shell, with a five-piece tail (telson and uropods).

These crustaceans usually inhabit a large shell of a gastropod, consequently only the cephalothorax and the first three pairs of legs are visible.