Its length is up to 105 mm, width up to 70 mm, and inflation up to 33 mm. In Chile its maximum controlled length is 87 mm.
This species is native to Chile and New Zealand.
Also, a self-sustaining population in the Menai Strait was deliberately introduced from the Fisheries Laboratory, Conwy, during the 1960s as an experiment to establish if they could form an alternative to the native oysters Ostrea edulis in fisheries, when the species was shown to be unsuitable because of low recruitment and vulnerability to parasites and pathogens the experiment was abandoned. O. chilensis has now spread to other areas of the Menai Strait and is regarded as an invasive species.
Whereas in Chile, its range limit is from Chiloé Island, Los Lagos region to Guaitecas Islands, Aysén region. Practically, nowadays it only exists in the wild in one natural bank, Pullinque, a sector located in the Quetalmahue Gulf of Ancud which was declared a genetic reserve in 1982, and as a marine reserve in 2003.
This bivalve is found from low tide to depths of up to 35 m. In Chile it lives attached to hard rocky or muddy bottoms, from intertidal to about 8 meters deep, in enclosed bays or areas protected from strong waves.
