Apollo 15 launched from Kennedy Space Center's Launch Complex 39A on July 26, 1971. The outward flight to the Moon's orbit saw only minor difficulties, and the mission entered lunar orbit without incident. The descent to the Moon by the LM Falcon, with Scott and Irwin aboard, took place on the late afternoon of July 30, with Scott as commander attempting the landing. Despite difficulties caused by the computer-controlled flight path being to the south of what was planned, Scott assumed manual control for the final descent, and successfully landed the Falcon within the designated landing zone.
Apollo 15 splashed down in the Pacific Ocean north of Honolulu on August 7, 1971. The first crew to land on the Moon and not be quarantined on return, the astronauts were flown to Houston, and after debriefing, were sent off on the usual circuit of addresses to Congress, celebrations and foreign trips that met returning Apollo astronauts. Scott regretted the lack of quarantine, which he felt would have given them time to recover from the flight, as the demands on their time were heavy.
The crew had arranged with a friend named Horst Eiermann to carry postal covers to the Moon in exchange for about $7,000 for each astronaut. Slayton had issued regulations that personal items taken in spacecraft be listed for his approval; this was not done for the covers through an error. Scott carried the covers into the CM in his spacesuit; they were transferred to the LM en route to the Moon, and landed there with the astronauts. Scott sent 100 of them to Eiermann, and in late 1971, against the astronauts' wishes, the covers were offered for sale by West German stamp dealer Hermann Sieger. The astronauts returned the money, but in April 1972, Slayton learned of the unauthorized covers, and had Scott, Worden and Irwin removed as backup crew members for Apollo 17. The matter became public in June 1972, and the astronauts were reprimanded for poor judgment by NASA and the Air Force the following month. The covers that the crew still had were initially impounded by NASA but were in 1983 returned to the astronauts in an out-of-court settlement, as the government felt it could not successfully defend the lawsuit, and that NASA either authorized the covers to be flown or was aware of them.
Agnew also gave the Apollo 15 crew the NASA Distinguished Service Medal. Scott earned his second Air Force Distinguished Service Medal for Apollo 15. On September 15, 1971, the city of Chicago hosted the Apollo 15 crew in a parade attended by more than 200,000 people. Mayor Daley presented the crew with honorary citizenship medals. On August 25, 1971, the Apollo 15 crew were honored with a ticker-tape parade in New York City. The city bestowed them with gold medals. Later that day, U.N. Secretary General Thant awarded the trio the first United Nations Peace Medal. At the Air Force Association's annual dinner dance in September 1971, the Apollo 15 crew were presented with the David C. Schilling Trophy, the association's top flight award. Scott presented the Air Force and Air Force Association with items they flew to the Moon: sheet music of "Into the Wild Blue Yonder" and a U.S. Air Force flag. The Apollo 15 crew and Robert Gilruth (director of the Manned Spacecraft Center) were awarded the 1971 Robert J. Collier Trophy, an annual award for the greatest achievement in aeronautics or astronautics. Scott received the De la Vaulx Medal, the Gold Space Medal, and the V.M. Komorav Diploma from Fédération Aéronautique Internationale for 1971 for his role in the Apollo 15 flight. Scott was awarded his third NASA Distinguished Service Medal in 1978.
Scott, Worden and Irwin were granted Honorary Doctorates of Astronautical Science from the University of Michigan in 1971. Scott was awarded an honorary doctor of science and technology degree from Jacksonville University in 2013. It was the first honorary degree bestowed by the university.