The first Avocet (AM-19) was launched 9 March 1918 by Baltimore Dry Dock and Shipbuilding Co., Baltimore Md.; sponsored by Miss Frances V. Imbach; commissioned 17 September 1918, Lieutenant C. Crone in command and reported to the 5th Naval District, where she operated until July 1919.
Between July and November 1919 Avocet was engaged in sweeping the North Sea mine fields. Upon her return to the United States 11 November, she continued on duty in the 5th Naval District until 1920 when she was assigned to the Pacific Fleet. Arriving at San Diego in January 1920, Avocet remained at various west coast ports until August 1921 when she proceeded to Pearl Harbor. In October 1921 she departed Pearl Harbor and steamed to Cavite, Philippine Islands. She was assigned to the 2d Division, Mine Detachment, Asiatic Fleet, and served with them until 3 April 1922 when she was placed out of commission at Cavite.
Avocet was recommissioned at Cavite 8 September 1925 and reported to the Aircraft Squadron, Asiatic Fleet, for duty as aircraft tender. Until 1938 she participated in training exercises and joint maneuvers in the Pacific. She assisted in the Naval Eclipse Expedition in the Philippines during 1929. Reclassified AVP-4, 22 January 1936, Avocet underwent conversion to a seaplane tender in March 1938.
She then served with Aircraft, Scouting Force, cruising in the Pacific with the fleet. She arrived at Pearl Harbor 4 June 1941 and remained on duty until May 1942. She was present when the Japanese attacked Pearl Harbor 7 December 1941, but escaped without casualties. Avocet departed Pearl Harbor 11 May 1942 and steamed to San Francisco where she underwent a yard overhaul.
On 24 July 1942 she departed Seattle for Kodiak, Alaska. Throughout the remainder of World War II Avocet served in the Alaskan and Aleutian theatres of operations as a unit of Patrol Wing 4. During the years, she tended patrol squadrons, transported personnel and cargo, and participated in patrol, survey, and salvage duties. Between 2 and 4 September 1942 she conducted rescue and salvage operations on the torpedoed seaplane tender Casco (AVP-12). She assisted in towing the damaged vessel to port and took on board a portion of her crew. Avocet returned to Seattle 16 October 1945; was decommissioned there 10 December l945, and sold 12 December 1946.
Avocet received one battle star for her World War II service.