Diogenes pugilator is a species of hermit crab, sometimes called the small hermit crab or south-claw hermit crab, with a maximum carapace length of 5.45 mm (0.215 in). It is found from the coast of Angola as far north as the North Sea, and eastwards through the Mediterranean Sea, Black Sea and Red Sea. Populations of D. pugilator may be kept in check by the predatory crab Liocarcinus depurator.