The U.S. spends $91 million annually on trials at the base, which houses 61 inmates.
The number of detainees at the U.S. base in Cuba is down to 78 but Congress resists plans to resettle the remainder within mainland facilities.
Transfers come just days before Obama visits Saudi Arabia for a meeting of Gulf Arab allies.
The two men were the first of a group of about a dozen who are expected to be transferred in coming weeks.
The president has been trying for years to make good on his pledge to close the facility.
After his release, 104 inmates remain at the maximum security facility.
Since Obama took office in 2009, some say Pentagon officials have been throwing up many bureaucratic obstacles.
How is Obama ever going to close Guantánamo if diplomatic assurances are worthless?
Cori Crider sat in Cuba 14 years ago and imagined what Shaker Aamer would be like. Today, he is finally free.
Younous Chekkouri's lawyers hope a short letter from the Justice Department will help free him.
Suspected of covering up a grisly death, David Martine was never charged with a crime, but never cleared either.
The Pentagon confirms that Abdul Shalabi has been released after 10 years at the camp.
Younis Chekkouri was repatriated to Morocco, but is being held in an undisclosed location as he is investigated.
Hassan's story offers a glimpse into the lives of dozens of men who say they've been accidentally ensnared in the war against Al-Qaeda.
Kerry noted that the issue was a pointed difference between the two nations.
The new rule ends a decade-long practice, and one that defense lawyers say brings comfort to their clients
The Navy decided not to discharge the man, who will be reassigned to a new position in New England.
The hostage Javier Espinosa was held for six months along with James Foley.
Abdul Rahim Abdul Razak al Janko says he was mistreated for 7 years at the prison.
Once thought to be a top Al-Qaeda lieutenant, he's mentioned 1,000 times in the Senate report on "enhanced interrogation techniques."
With Sunday's release, the Guantanamo prisoner population has been whittled down to 136.
Obama administration to appeal district court's decision to release tapes.
The United Nations Committee Against Torture questioned U.S. representatives on issues ranging from force-feedings at Guantanamo to police brutality in Ferguson.
His administration is fighting to keep 2,000-plus images from the public.