With the outbreak of World War II, Villiers was commissioned as a Lieutenant in the Royal Naval Reserve in 1940. He was assigned to a convoy of 24 LCI(L)'s, or Landing craft, Infantry (Large). Ordered to deliver them across the Atlantic, with a 40 percent loss rate expected, Villiers got all but one safely across. He commanded "flights" of LCI(L)'s on D-Day in the Battle of Normandy, the Invasion of Sicily, and the Burma Campaign in the Far East. By the end of the War, Villiers had been promoted to Commander and awarded the British Distinguished Service Cross.