For the first time since Labor lost control of Australia's borders, there are no children in a regional processing country.
The final four children on Nauru departed for the United States with their families Wednesday afternoon.
They were among a group of 37 refugees from Nauru and Manus Island to be resettled in the United States this week, bringing the total number to 493.
Further departures are expected to occur in the coming weeks.
Minister for Immigration, Citizenship and Multicultural Affairs David Coleman said the Government's strong border protection policies meant we've been able to stop the boats and work through the backlog of cases Labor created when 50,000 people arrived on 800 boats on their watch.
"When we came to office there were 2,000 children in onshore detention in Australia – we got them all out. We have now removed all children from Nauru," Mr Coleman said.
"This is something the Government has been working on for some time, quietly and in a way that would not impact our border protection policies.
"Our track record on this issue is clear and it is a massive contrast with what was seen under the previous Labor government.
"By weakening our borders, Labor put more than 8000 children in overcrowded onshore detention centres and in regional processing countries.
"We have got the kids out of onshore detention and off Nauru, we have stopped the flow of unlawful boat arrivals and deaths at sea, and we have increased our humanitarian program by 35 percent since coming into Government.
"Labor's law that was passed through Parliament this month will end offshore processing as we know it, and give people smugglers the marketing material they crave. This shows once again that Labor cannot be trusted on border security."