Breeding begins around the age of six (4) (5), with males returning to the breeding colony in August, and females following shortly after (4). Single males attract females by standing upright with their wings extended and repeatedly pumping their chest. Nests are shallow dug holes in the ground, lined with twigs and small branches, usually built under trees and shrubs to shield it from the sun (5). Two eggs are typically laid in late September to early October, the first, smaller egg being laid four to five days before the second, larger egg (4) (5). Both parents take turns incubating the eggs for the first 10 days, after which the male goes to the ocean to feed while the female incubates the eggs for 12 days straight and then vice versa. A mutual display of bowing and trumpeting (extending the beak vertically in the air and calling out) is performed when the male returns to the nest, helping to cement the bond (5). For the first three weeks after hatching, the male stands guard, protecting the chicks from predators, while the female forages and returns daily to feed the young (4) (5) (6). As with most penguins, both chicks rarely survive, with many pairs losing an egg during incubation, or one chick usually dying before the end of the guard stage. After the guard stage, the chick begins to explore its surroundings, creching with other nearby chicks, but returning to the nest to be fed. At 11 weeks the young fledge (4).
Little has been recorded on the diet of the Snares crested penguin, but krill, squid and fish are known to be included (3) (5).