The occasional individual has been found north to Shark Bay, Western Australia.
Adult males are dark blackish brown and have a mane of longer coarser hairs over their shoulders.
Adult females are silver grey above and creamy yellow beneath, fading to brownish. Pups are born chocolate brown with a pale fawn crown, and moult to a juvenile coat similar to that of adult females at about 2 months. Females reach sexual maturity at 4.5-6 years and males at 6 or more. Different breeding locations have different seasons for pupping. Australian sea lion females prefer sandy beaches and smooth rocks for giving birth and have been known to move inland.