Olive Davis left Toowoomba General Hospital to join the Australian Army Nursing Service at Enoggera Military Hospital, Brisbane in November 1917 (with her co-worker Estelle Fisher). She enlisted a year later and embarked for India. She nursed at 34th Welsh General Hospital at Deolali, 18th British General Hospital at Gharial and 19th British Hospital at Lahore between December 1918 and October 1919 and then returned in Brisbane.