Sand colored with a velvety texture, the species expresses pentamerism or pentaradial symmetry as adults.

The five gently tapering arms have conspicuous bands of long white marginal spines in groups of three.

They are usually found on muddy sediment and are most active at night, burying themselves under the sand during the day.

Luidia sarsii larva develop from a fertilized egg and are unique in a number of respects.

During metamorphosis the juvenile migrates to the outside and detaches from the swimming larval bipinnaria stage.