South Korea's Yonhap News agency quotes a military source as saying Boeing will win the $350 million contract after its rival, European Aeronautic Defence and Space Company, dropped out of the bidding.
"Boeing is offering the 747-8 model and the DAPA will evaluate the plane's performance by October," the source said.
South Korea plans to buy a presidential jet by 2014 to replace its presidential plane put into service in 1985. Currently, President Lee Myung-bak is using a Boeing 747-400 jet for overseas trips under a five-year lease contract with Korean Air.
South Korean officials plan to begin evaluating Boeing's offer by October, SeattlePI.com reported.
The 747-8 is the largest commercial aircraft built in the United States.