The exercises, dubbed "Freedom Shield", will be held from March 13-23 to strengthen the allies' combined defensive posture, the two militaries said in a statement released at a briefing in Seoul.
"Freedom Shield is designed to strengthen defense and response capabilities of the Alliance by focusing within the exercise scenario on things such as the changing security environment, DPRK aggression and lessons learned from recent wars and conflicts," the statement said, using the initials of North Korea's official name.
Past drills have drawn sharp reactions from North Korea, including missile launches and nuclear threats. Pyongyang has said such joint military operations are proof that Washington and its allies are hostile.
When asked about the North's possible reaction, Colonel Isaac Taylor, a spokesman for U.S. Forces Korea (USFK), said the drills were routine and purely defensive.
South Korean officials have noted North Korea is also conducting annual wintertime drills.
Freedom Shield will feature field exercises on a scale not seen since about 2017, before former U.S. President Donald Trump scaled back public drills to facilitate diplomacy with North Korea.
Talks with Pyongyang are long stalled, but in intervening years Covid restrictions kept drills to a limited size. With a record number of missile launches from North Korea last year, and South Korea's lifting of anti-pandemic measures, the allies are returning to large-scale drills as a warning to Pyongyang.
Over the past month South Korean and U.S. special operations troops conducted a live-fire drill named "Teak Knife", which included a U.S. AC-130J gunship that participated in joint drills for the first time, firing guided missiles and bombs as well as 30mm and 105mm guns.