Detached from the Reserve Force, Pacific Fleet on 17 April 1914, "South Dakota" made a cruise southward into Mexican waters in May and another westward to the Hawaiian Islands in August. She returned to Bremerton on 14 September and reverted to reserve status on 28 September. She was the flagship of the Reserve Force, Pacific Fleet, from 21 January 1915 until relieved by the protected cruiser on 5 February 1916. She remained in reduced commission through 1916, and on 5 April 1917 she was again placed in full commission.