The Salmonella serotypes S. Cerro and S. Newport were isolated from New Zealand sea lions (Phocarctos hookeri) and feral pigs on the Auckland Islands in the New Zealand subantarctic region. The isolates were typed by pulsed-field gel electrophoresis using Xba1 as the restriction enzyme. The isolates were indistinguishable, which suggests that Salmonella infection cycles between sea lions and pigs in this environment. Apart from a previous isolation from a single New Zealand fur seal (Arctocephalus forsteri), S. Newport has not been recorded in any animals from New Zealand, but it is associated with gastroenteritis in humans. Contamination of the marine environment by human waste is a possible source of infection for marine mammals and warrants further investigation.