The last 35 detainees were taken from the facility on Sunday and transferred to mainland facilities.
Immigration Minister David Coleman says the centre will be kept in a state of "operational readiness" so it can be re-opened at short notice.
"This Government has stopped the boats, stopped the evil people smuggling trade and removed those children from detention," he said in a statement on Thursday night.
He said the centre was one of many that had closed since 2013, which had saved the government more than $500 million.
The Australian government opened the most recent immigration facility on Christmas Island in 2008.
The island was the scene of a mass tragedy in 2010, when 50 asylum seekers drowned when their boat sank after hitting rocks near Flying Fish Cove.
