 Human habitation of the Australian continent is estimated to have begun between 42 @,@ 000 and 48 @,@ 000 years ago , possibly with the migration of people by land bridges and short sea @-@ crossings from what is now Southeast Asia . These first inhabitants may have been ancestors of modern Indigenous Australians . At the time of European settlement in the late 18th century , most Indigenous Australians were hunter @-@ gatherers , with a complex oral culture and spiritual values based on reverence for the land and a belief in the Dreamtime . The Torres Strait Islanders , ethnically Melanesian , were originally horticulturists and hunter @-@ gatherers . The northern coasts and waters of Australia were visited sporadically by fishermen from Maritime Southeast Asia . 
