Ibacus ciliatus is a broad slipper lobster, with a carapace length of up to 80 millimetres (3.1 in), and a total length up to 23 centimetres (9.1 in). It is typically a uniform reddish brown in colour; the tail fan (uropods and telson) can be a browner or a yellower hue.

Biology Glossary (e.g. epibenthic) It has a maximum total length of 23 cm; and a carapace length of 4 to 7.6 cm (male) and 4 to 8 cm (female), 6 to 8 cm (ovigerous female) (Ref. 4). Occurs at a depth range from 49 to 314 m, mostly between 100 and 250 m, and it is found on soft substrates of sand, mud or clay (Ref. 4).