The Australian continent was first settled when ancestors of Indigenous Australians arrived via the islands of Maritime Southeast Asia and New Guinea over 50,000 years ago.

European colonization began in 1788 with the establishment of a British penal colony in New South Wales. From early federation in 1901, Australia maintained the White Australia policy, which forbade the entrance in Australia of people of non-European ethnic origins. Following World War II, the policy began to be relaxed and it was finally abolished in 1973. Since 1945, more than 7 million people have settled in Australia.

Between 1788 and the Second World War, the vast majority of settlers and immigrants came from the British Isles (principally England, Ireland and Scotland), although there was significant immigration from China and Germany during the 19th century. In the decades immediately following the Second World War, Australia received a large wave of immigration from across Europe, with many more immigrants arriving from Southern and Eastern Europe than in previous decades. Since the end of the White Australia policy in 1973, Australia has pursued an official policy of multiculturalism,[2] and there has been a large and continuing wave of immigration from across the world, with Asia being the largest source of immigrants in the 21st century. In 2019–20, immigration to Australia came to a halt during the COVID-19 pandemic, which in turn saw a shrinkage of the Australian population for the first time since World War

Australia is a signatory to the Convention relating to the Status of Refugees and has resettled many asylum seekers. In recent years, Australia’s policy of mandatory detention of unauthorized arrivals by boat has attracted controversy.

Social cohesion:
The impact that immigration has on social cohesion in Australia is not clear. According to a 2018 report by the Scanlon Report, between 80 and 82% of Australians felt that immigration had a positive impact on Australian society. Australians under the age of 30 were twice as likely to feel positively about immigration as Australians over the age of 60 were. A follow-up report in 2019 found that 85% of Australians polled felt that multiculturalism had made a positive impact on Australia.