Acanthochitona crinita is oval, less than half as long as it is wide, and grows to a length of about 34 mm (1.34 in).

[2] Like other chitons, it bears a protective shell formed from eight articulating valves on its dorsal surface, these being embedded in a tough muscular girdle.

[3][4] The valves in this species are strongly arched with moderately rounded keels, and are finely sculpted longitudinally.

It is found on rocks on the lower shore and shallow sublittoral zone, especially areas with strong surf action.

The larvae have a short planktonic trochophore larval phase before settling to the seabed, undergoing metamorphosis and developing into juvenile chitons with six valve plates, which soon hide under stones.