 USS Cummings served in the Pacific Fleet in the late 1930s, participating in numerous individual and fleet training exercises. In 1940, she served on security patrols off the west coast. Cummings went on a goodwill visit to several ports in the South Pacific, including Auckland, New Zealand, and Tahiti. The destroyer was hit by fragments while docked in Pearl Harbor during the Japanese attack, and suffered a few casualties. She escorted convoys between Pearl Harbor and the west coast for the first six months of World War II. In June 1942, she was transferred to convoy escort duties in the South Pacific until August, when she had an overhaul in San Francisco, and then returned to her role as a convoy escort in the South Pacific.
