After fitting out as an auxiliary cruiser, the ship joined in the Spanish–American War and patrolled the coastal waters between Block Island and Cape Henlopen until 27 May. That day, "Yankee" stopped at Tompkinsville, New York to coal ship. On 29 May, she returned to sea and shaped a southerly course to join the fleet off Cuba. "En route", she touched briefly at St. Nicholas Mole, Haiti, on the evening of 2 June and then continued on toward Cuba. Early the following morning, "Yankee" joined the blockade off Santiago de Cuba and conducted patrols there for the next five days.