The children will be flown with their families as part of a resettlement deal agreed with Washington.
Australia has held asylum seekers arriving by sea on Nauru since detentions began there in 2013.
Last August it held 109 children. Australia refused to resettle them under its tough immigration policies.
In a statement issued on Sunday, Australian Prime Minister Scott Morrison said "every asylum seeker child has now been removed from Nauru... or has a clear path off the island".
He said that children would no longer be detained there.