Oswald Watt drowned at Bilgola Beach, near Newport, New South Wales, on 21 May 1921. Cuts and bruising on his body indicated that he had slipped on rocks, struck his head, and rolled unconscious into relatively shallow water. Survived by his 15-year-old son, he was accorded a military funeral two days later at St Jude's Church, Randwick. Members of the AFC, Royal Air Force, and Australian Aero Club formed a guard of honour at the service, one of the largest in the suburb's history, which also included representatives of the Royal Australian Navy and Australian Army. Among the tributes was a floral wreath from an anonymous group of French admirers, and another that was dropped by parachute from a low-flying plane. On 31 May, Watt's body was cremated and his ashes interred in the family vault at St Jude's.