Metro will open two hours early Sunday to accommodate those running in the Army Ten-Miler.
Both Metrorail and bus service will begin at 5 a.m. Oct. 20.
Riders going to the race are advised to get off at the Pentagon station on the Blue and Yellow lines. Additional trains will run on both lines between 6 a.m. and 8:40 a.m. and between 11:15 a.m. and 12:40 p.m., officials said.
Those connecting from the Red Line should be aware that buses will replace trains between Silver Spring and Fort Totten stations. The Takoma station will be closed.
At Green line's Greenbelt stations, trains will arrive and depart every 20 to 25 minutes due to construction.
The Blue, Yellow and Orange lines will have regular weekend service.
WMATA says an agreement with the organizers of the Army Ten-Miler funded the additional two hours of Metro service.