with the ships of Battle Force to participate in Fleet Problem XXI, conducted in Hawaiian waters. Though nominally retaining San Diego as her home port, Warrington was based at Pearl Harbor for most of her remaining peacetime service. From April 1940 to April 1941, she returned to the West Coast only twice: once in June 1940 for repairs after the conclusion of the Fleet exercise and again in late November and early December of that year. After 12 months of training out of Pearl Harbor, frequently with submarines engaged in torpedo practice, Warrington departed Hawaii on 18 April 1941 to augment the forces engaged in the so-called "Neutrality Patrol". After passing back through the Panama Canal on 7 May, she continued on to Guantanamo Bay, Cuba. There, she became part of a patrol force composed of the cruisers , , and destroyer . Her area of operations encompassed the eastern Caribbean and the western Atlantic from the West Indies south to about 12° south latitude. In addition to patrolling, she later began intermittent escort duties; and, in fact, her last assignment during the "Neutrality Patrol" period consisted of a voyage in company with the cruiser to escort SS Acadia from Recife, Brazil, to Puerto Rico. She arrived at San Juan on 3 November; then headed north for a two-day visit at Norfolk; and entered the Charleston Navy Yard on the 9th for repairs. World War II She was moored at Charleston on 7 December when the news arrived that the Japanese had attacked Pearl Harbor. Warrington put to sea the following day to conduct war patrols along the Atlantic coast from Norfolk to Newport. Late in December, she rendezvoused with and escorted the British battleship into Norfolk on the 21st. For another three weeks, the destroyer patrolled the eastern seaboard as far north as the Massachusetts coast and then headed south on her way to a new area of operations. On 17 January 1942, the warship arrived in Balboa at the Pacific terminus of the Panama Canal where she reported for duty with the Southeast Pacific Force. Based at Balboa, she operated with the other ships of the Southeast Pacific Force, three cruisers and another destroyer, for the next 16 months. She had two primary missions to perform: escorting merchant, supply, and troop ships between Panama and the Society Islands and patrolling for submarines in the southeastern Pacific as far