Fleet was established under the command of Rear Admiral Alfred Reynolds. This organization was established in response to severe manpower shortages and was not similar in any respect to the contemporary reserve or "mothball" fleet. By 1 June, Truxtun joined the Pacific Reserve Fleet; however, she remained somewhat active, periodically putting to sea to check her machinery and to maintain herself "...in constant readiness for sea." Her reserve status was short-lived. She was placed back in full commission on 12 October and resumed normal activity along the coast. On two occasions, in the summer of 1914 and again in the summer of 1916, the torpedo boat destroyer steamed to Mexican waters to protect American interests during the series of political convulsions that plagued that nation during the second decade of the twentieth century. By July 1916, she had returned to semi-inactivity as a unit of the reserve division of the Coast Torpedo Force — later re-designated Division 2 (Reserve), Coast Torpedo Force. As before, however, she conducted sporadic cruises along the California coast to maintain herself in a state of readiness. World War I On 18 February 1917, Truxtun was returned to full commission for the third and final time, Lieutenant James G. Ware in command. Initially, she was assigned to patrol duty in the area of the Panama Canal. On 6 April, the day the United States entered World War I, she departed Colon harbor and headed south to Puerto Colombia, Colombia, where she watched the German ship which was anchored in the harbor. She was relieved by on 14 April and returned to Colon the following day. For almost three months, she patrolled the Pacific coastal waters of Panama and Colombia, periodically doubling as a submarine tender. On Independence Day 1917, she transited the Panama Canal and, the following day, departed Balboa, Panama, in company with Stewart, , and . The four destroyers reached Hampton Roads on 13 July. Through the end of August, Truxtun patrolled Chesapeake Bay and conducted maneuvers off the coast. She made port calls at New York and Philadelphia, on one occasion acting in the escort for . On 31 August, Truxtun departed Philadelphia for duty in the Azores. After a short stop-over in Bermuda, she arrived at Ponta Delgada on 16 September. The destroyer operated from Ponta Delgada until early December. She and Whipple met on 30 September and escorted her into Ponta