King penguins breed in colonies of up to 40,000 pairs on South Georgia (200,000 pairs in 32 colonies) and Falkland Islands (400 pairs), but are extinct on Tierra del Fuego. Another subspecies forms much larger colonies in other parts of the Southern Ocean. They have extended breeding season, with birds present at colonies at any time of the year. Chicks take 10-13 months to fledge, so each pair only breeds twice every three years. Their population is currently slowly rising.

King penguin is the largest breeding species of the Scotia Sea. Its even larger relative, emperor penguin (A. forsteri), breeds further south and visits the area during non-breeding season, but is very rarely seen here. King penguins usually breed on flat snow-free beaches and adjacent level areas. They are less migratory than some other species, but feed on fish and squid 40-1,000 km from the colony. They can dive to almost 300 m and are fast swimmers, but not as good at porpoising as some smaller penguins.