1938. Humphreys recommissioned once more 26 September 1939 as the beginning of the war in Europe necessitated an increase in America's readiness. Humphreys conducted shakedown off San Diego and sailed 13 November to join the Neutrality Patrol in the Caribbean, designed to protect American shipping. During May and June 1940 the ship took part in a sound school at Newport to improve her antisubmarine capability, and sailed 4 December from Norfolk, Virginia for San Diego, where she arrived 2 days before Christmas. There she continued Neutrality Patrol duty and engaged in antisubmarine training off California. World War II Humphreys was in San Diego when the Japanese attack on Pearl Harbor brought the United States into the war 7 December 1941. During the critical early months she operated as a coastal escort ship between San Pedro and Seattle, Washington but in May she sailed northward to Kodiak, Alaska, arriving 31 May 1942. In the bleak Aleutian Islands she escorted transports, patrolled American-held islands, and engaged in exercises with Honolulu, Indianapolis, and several destroyers. Humphreys arrived at San Francisco 11 November and entered Mare Island Navy Yard for conversion to high-speed transport. She was reclassified APD-12 on 1 December 1942; and, following shakedown training, arrived at Pearl Harbor 31 December to prepare for duty in the western Pacific. After amphibious training in Hawaiian waters, the ship sailed to Noumea 22 January 1943 and began ferrying troops and supplies from advance bases to Guadalcanal, Tulagi, and Florida Island. During these critical months as the ship repeatedly steamed to the Solomon Islands in support of amphibious assaults, she often fought off bombing and strafing attacks by Japanese aircraft. After training landings Humphreys embarked elements of the 1st Cavalry Division at Nouméa and transported them to Townsville, Australia, in preparation for Operation Chronicle, landings on Woodlark and Kiriwina Islands. Arriving Townsville 20 May 1943, the ship sailed for Milne Bay 21 June, and from there landed troops and equipment on Woodlark 23 June without enemy opposition. This first landing of the long New Guinea campaign was also the first for Admiral Daniel E. Barbey's 7th Fleet Amphibious Force ("VII Phib"), and provided invaluable experience for the numerous amphibious operations to come. Humphreys sailed to Brisbane for repairs during July and August, and returned to Milne Bay 15 August 1943. There she prepared for VII Phib's next move up the coast of New Guinea to Lae.