"We are wasting hundreds of millions of dollars to keep fewer than 60 people in a detention facility in Cuba. That’s not strength … And I will continue to do all that I can to remove this blot on our national honor," Obama said.
Its population was reduced last week after a Yemeni man was transferred to an island off the West Africa coast.
President Obama, who was speaking as US commander-in-chief for the last time before he leaves office in January, made a pre-election pledge in 2008 to close the detention facility by 2010. His successor, Donald Trump, said he would keep the prison running.