The men were identified as Saad Muhammed Husayn Qahtani, 35, and Hamood Abdulla Hamood, 48, who returned as Saudi nationals, the Miami Herald reported Monday.
Neither had ever been charged with a crime, the U.S. government said. They were among the last 11 Saudi citizens at the prison.
The transfers reduced the prison camps population to 160 detainees.
Government sources told the Herald the Saudi repatriations during the weekend were voluntary and that a federal task force determined the men were eligible for transfer, "subject to appropriate security measures."
"The United States coordinated with the government of the kingdom of Saudi Arabia to ensure that these transfers took place with appropriate security assurances and in a way that is consistent with our humane treatment policy," Paul Lewis, the Defense Department's special envoy for the detention facility's closure, said in a statement.
Separately Sudan's news agency reported the last two Sudanese captives at the Guantanamo prison facility should be repatriated later this week, the Herald said.
Meanwhile, the Herald said, the five men accused of plotting the Sept. 11, 2001, terror attacks on the United States were expected back at the facility's war court Tuesday.