Females reach sexual maturity between 4 and 6 years and will give birth to a single pup more or less every year until their death at on average 14 - 17 years. Females mate 68 days alter the birth of their pup, and then have delayed implantation; the egg is fertilised, but it does not implant in the uterine wall for another 3 months. Gestation is therefore about 9 months, even though the female is mated 360 days before she gives birth.

The breeding season is from mid-November to Mid-January. Pups are suckled for about 300 days, though some will continue to suckle into their second year. Females alternate foraging trips (periods of 1-20 days at sea) to feed, with attendance periods (1-2 days), where they are at the rookery to suckle the pup.

Pups start to feed on solid food before weaning, and spend a large proportion of time playing with other pups and objects such as seaweed and reef fish. It is possible that they attain skills for later life (such as foraging, anti-predator behaviour and also social behaviour) during this period. After weaning pups disperse.