Inachus dorsettensis has a triangular shaped shell (carapace) with long slender legs and a U-shaped snout-like projection (rostrum). It has four small spines on the anterior part of carapace upper surface. The carapace is reddish brown in colour. The underside of the claw bearing limb (cheliped) is bright pink or violet in colour especially the segment behind the claw (the carpus). Female chelipeds are small and the claw (propodus) is somewhat compressed. Male chelipeds are large, with a short and swollen propodus. The carapace length is around 3.5 cm, with a breadth of 2.7 cm. The eye stalks are also totally visible from above.Inachus dorsettensis covers itself in tiny pieces of sponge and sea weed to provide camouflage. It is often found living in the tentacles of the snakelocks anemone (see Ingle, 1996 for further details).