was assigned to the Naval Base at Cardiff, Wales in January 1919, becoming the Naval Port Officer at Cardiff from July to August 1919, when he was transferred to the U.S. Naval Headquarters in London. In November 1919 he became Naval Port Officer, Constantinople, Turkey. In October 1920, he also became operations officer and flag secretary to Rear Admiral Mark L. Bristol, Commander U.S. Naval Detachment in Turkish Waters and High Commissioner to Turkey. Barbey ceased to be Naval Port Officer in July 1921, but continued as flag secretary to Admiral Bristol. During this time, Barbey served as the U.S. delegate on the Allied Commission for the Control of Trade with Turkey and as an observer with the White Army in the Crimea. Returning to the U.S. in February 1922, he served briefly on the cargo ship before becoming assistant engineering officer of the battleship in the Pacific. He was promoted to lieutenant commander on 15 October 1922. Continuing the pattern of alternating duty afloat and ashore, he then spent two years as Officer in Charge of the Portland Navy Recruiting Station, before returning to the Atlantic as engineering officer of the light cruiser in June 1925. From February 1927 to June 1928, he was executive officer of the oil tanker . He then spent the next three years as aide to the Superintendent of the U.S. Naval Academy, Rear Admiral Samuel S. Robison. From June 1931 to June 1933 he commanded the destroyer . He then spent two years as an inspector of ordnance at the Mare Island Naval Ammunition Depot in California, where he was promoted to the rank of commander in September 1933. In February 1935, he was posted to the battleship as damage control officer. He briefly commanded the before becoming Commander of Destroyer Division 17 in the Pacific. In June 1937 Barbey was assigned to War Plans Section of the Bureau of Navigation in Washington, D.C. During this assignment, he worked on mobilization plans, and developed an interest in amphibious warfare from studying reports of Japanese amphibious operations in the Second Sino-Japanese War. He was particularly intrigued by photographs of special landing craft with hinged bow ramps. In 1940 he produced Fleet Training Publication 167 – Landing Operations Doctrine, United States Navy (FTP 167). This would become the Navy's "bible" of amphibious operations, and would remain in use throughout World War II. He was promoted