Dorothea put to sea from Philadelphia on 14 June 1898 and patrolled from Key West, Florida, to Havana, Cuba, until returning to Hampton Roads on 28 August.

She was placed in full commission there on 20 April 1917 following American entry into World War I and sailed on 2 July for duty on the East Coast.

The ship's company of Dorothea was the first Ohio National Guard unit activated for service in the First World War.

On 8 January, she sailed from New Orleans for Havana, Cuba, where she served in the instruction of Cuban naval officers, returning to Key West for stores and repairs occasionally.

From 13 November 1918, Dorothea served as a transport in Cuban, Puerto Rican, and Dominican waters, operating briefly under the command of Harry Shepard Knapp, the military governor of Santo Domingo.