It is found in deep water in the eastern Atlantic Ocean and the Mediterranean Sea.

Cidaris cidaris has a small central test from which project a number of long, blunt, widely separated primary spines and a dense covering of short secondary spines.

[2] The sea urchin often has bits of algae, sponge or other organisms adhering to the spines.

[2] Cidaris cidaris is found in the eastern Atlantic Ocean and the Mediterranean Sea in deep water on coral, rock and gravel bottoms.

It is also found on knolls and seamounts[1] at depths down to about 1,800 metres (5,900 ft).