The amphibious drill will start March 28 and run until April 1 at the port of Pohang, some 360 kilometers (223 miles) south of Seoul, the US-South Korea Combined Forces Command said in a statement.
It will include some 1,000 US Marines, three US amphibious ships and 3,000 South Koreans, Yonhap news agency said.
US sailors and marines from the Bonhomme Richard Amphibious Ready Group and the 31st Marine Expeditionary Unit (MEU) based in Okinawa, Japan, are also participating in the drill, known as Ssangyong in South Korea and the Korean Marine Exchange Program (KMEP) in the United States.
The scale of the drill has been downgraded compared with last year, though it marks the peak of the eight-week Foal Eagle joint US-South Korea military exercise which started on March 2 and is scheduled to end on April 24.
Also beginning early March was the Key Resolve exercise -- a computer-simulated command post drill that rehearsed various conflict scenarios and involved around 10,000 South Korean and 8,600 US troops.
The exchange was triggered by a three-hour North Korean live-fire exercise that dropped shells into South Korean waters, but was limited to untargeted shelling into the sea.
Annual drills always trigger a surge in military tensions between the two Koreas, which remain technically at war because the 1950-53 Korean conflict ended with a ceasefire rather than a peace treaty.
The United States and South Korea insist their joint military exercises are defensive in nature, but North Korea claims that they, especially the landing drill, are designed to rehearse invasion.
