Noriega's eight-year rule over Panama ended after the United States invaded the county on Dec. 20, 1989, to force him from power.
He is being held in the Federal Correctional Institution in Miami on drug trafficking and money laundering charges.
Noriega was sentenced to a 30-year term for protecting Colombian cocaine shipments through Panama in the 1980s but received deductions in his punishment for good behavior. Noriega's release in 2007 was first scheduled more than three years ago.
The exact date, Sept. 9, was posted on the U.S. Bureau of Prisons Web site more than a year ago.
"I'd say that is a firm date," Noriega's attorney Frank Rubino said Tuesday.
Noriega, 70, had parole hearings in 2002 and 2004 to try to cut short his 30-year sentence. He was not recommended for parole either time.
Rubino said his client plans to waive any deportation hearings and try to board a plane back to Panama the day he is released from prison.
"He wants to go back to Panama and he wants to enjoy his grandchildren in quiet retirement," Rubino said.
Yet many in Panama said they doubted Noriega would return.
"I'm sure he will choose another country," retired Gen. Ruben Dario Paredes, who headed Panama's military from 1981 to 1983, said Wednesday. "In Panama, unlike in the U.S., he will find much worse conditions."
Noriega has received two 20-year sentences in Panama for the 1985 decapitation of dissident leader Hugo Spadafora and the 1989 slaying of Maj. Moises Giroldi, who tried to overthrow him. Rubino said Noriega will fight the charges.
"When he goes back to Panama, that case will be able to be reopened. Then he'll be able to adequately defend himself on that case," Rubino said.