The South Island is the southern island of mainland New Zealand.
South Island may also refer to:
South Island (McDonald Islands) South Island (South Australia), in Pondalowie Bay South Island, County Down, a townland in County Down, Northern Ireland Yuzhny Island, the southern of the two large islands of Novaya Zemlya South Island, Cocos (Keeling) Islands Suðuroy (South Island in Faroese), the southernmost of the Faroe Islands South Island (Kenya), an island on Lake Turkana, Kenya
See also Austronesia South Island line South Island line (West) South Island School North Island (disambiguation)