After fitting out, "Vestal" departed her conversion yard on 26 October for Hampton Roads, Virginia, where she conducted her shakedown between 29 October to 10 November. After touching at Key West, Florida, for coal on 14 November, "Vestal" moved on to Pensacola, Florida, her base for operations as a repair ship for the Atlantic Fleet. She was attached to the Atlantic fleet and served along the east coast and in the West Indies until spring of 1914 when she was dispatched along with other ships for the occupation of the Mexican port of Vera Cruz. The auxiliary vessel provided repair services at Vera Cruz from 2 May to 20 September before she sailed for Boston, escorting the cruiser "Salem" to the navy yard there for overhaul. As of December 1914, Commander U.T. Holmes was the commanding officer and Lieutenant Commander L.J. Connelly performed as executive officer, Lieutenants E.G. Oberlin and F.M. Perkins serving as staff officers.