Olympia's last act of service was the ceremonious transportation of the American Unknown Soldier of World War I from France to the United States. Olympia was chosen for this honor due to her significance as Admiral Dewey's flagship and for her near perfect twenty-seven year record of success. With the Navy ready to retire Olympia, it only seemed fitting that such a momentous duty would be conducted by the most famous active vessel of the time.
Leaving Le Havre, France and braving a stormy and dangerous voyage across the Atlantic in October 1921, Olympia delivered the Unknown Soldier in time for the anniversary of Armistice Day, November 11, now known as Veterans' Day. On that day in 1921, the Unknown Soldier was laid to rest at Arlington National Cemetery; today, the Tomb of the Unknown is one of the most famous and symbolic memorials in the United States.