It may grow up to 150 millimetres (5.9 in) long, and may weigh up to 900 grams (2.0 lb).[6] The carapace is wider at the front, reddish brown in color, with ten white spots.[2] Ranina ranina is mainly nocturnal, and remains buried in the sand during the day.[2] Ranina ranina is easily distinguished from other crab species in its habitat due to its red carapace and elongated midsection.[6]