Admiral George Dewey purchased her for the U.S. Navy in Hong Kong, China, on 9 April 1898, just before his Asiatic Squadron sailed for the Philippine Islands at the beginning of the Spanish–American War.

Despite orders to the contrary, Dewey did not commission Zafiro into the U.S. Navy, so she would technically be a merchant ship and, thus, would be able to access neutral ports, which greatly simplified the squadron's logistics.

[1] In any event, Zafiro departed Hong Kong with Dewey's squadron in April 1898 and served with it as a collier and supply ship during the Battle of Manila Bay and the ensuing Philippine campaign.

Those movements—in support of the United States Army's suppression of the Philippine insurrection and campaigns against the Moslem Moro tribesmen—took her to a host of exotic places and the length and breadth of the islands.

On 20 August 1919, she was re-registered in Panama as the Belen Quezada, the first international "flag of convenience" vessel, to run alcohol between Canada and the United States during Prohibition.