It typically grows to a length of 30 cm (12 in) and is a reddish-brown color with stripes along the legs, and has a pair of enlarged antennae but no claws.

Adults are nocturnal and migratory, living among rocks at depths of up to 65 m (213 ft), and feeding on sea urchins, clams, mussels and worms.

The spiny lobster is eaten by various fish, octopuses and sea otters, but can defend itself with a loud noise produced by its antennae.

[3] Juveniles generally inhabit rocky habitats at a depth of 0–4 m (0–13 ft) with dense plant cover, especially the surf grass Phyllospadix torreyi.

[7] California spiny lobsters are nocturnal,[3] hiding in crevices during the day, with only the tips of their long antennae showing, as a means of avoiding predators.

[9] This activity is important in limiting sea urchin populations, and so maintaining healthy seabed communities.

[5] Because all the hard parts are lost at each molt, the life span of mature spiny lobsters is uncertain;[5] they are thought to live for 50 years or more.

[12] The puerulus larvae settle to the sea floor when the water is near its maximum temperature, which in Baja California is in the fall.

[3] Recreational fishermen are allowed to catch lobsters with hoop nets or by SCUBA diving or free-diving; almost all come from California, with only small numbers from other U.S. states.

[18] In Mexico, spiny lobsters are an important commercial resource, representing the fifth most valuable fishery, worth US$18 million.

[7] The main legal restrictions on fishing for California spiny lobster in Mexico are a minimum landing size of 82.5 mm (3.25 in), the prohibition of catching berried females, and a closed season:[7] from February 16 to September 14, fishing for spiny lobsters is prohibited in a region which moves south along Mexico's Pacific coast during the season.

[3] The preferred common name of the United States Fish and Wildlife Service is simply spiny lobster.

[5] John Witt Randall described the species in the Journal of the Academy of Natural Sciences of Philadelphia in 1840, based on material given to him by Thomas Nuttall.

[15] The exact locality is not known, being given only as "Upper California", but the most likely sources are the places where Nuttall was most active, namely Santa Barbara and San Diego.