Nero was once again placed in full service on 29 April 1914 and, three days later, resumed her logistic operations, cruising from Bremerton to La Paz. Assigned to the Pacific Fleet on 5 June 1915, the collier continued her operations on into 1917. On 19 July, she departed San Francisco for New York, to meet the demand for auxiliaries in the Atlantic due to the increasing scope of U.S. naval operations in World War I. Passing through the Panama Canal on 2 August, Nero arrived Norfolk on the 18th. She sailed for Europe via the Azores on 11 September and shortly after her arrival at Queenstown, Ireland on 13 October, was assigned to duty with the newly formed Naval Overseas Transportation Service.
