After commissioning, "Marblehead" departed Boston for shakedown in the English Channel and Mediterranean. In 1925, she visited Australia, stopping en route in the Samoan and Society Islands and, on her return, in the Galápagos Islands. A year after her return, "Marblehead" was underway again on an extended voyage. Early in 1927, she cruised off Bluefields and Bragman's Bluffs, Nicaragua, her mission there to aid American efforts to bring together and reconcile the various political factions then fighting in that country. With one exception, Augusto César Sandino, faction leaders agreed to the terms of the Peace of Tipitapa on 4 May 1927, and the United States was requested to supervise elections in 1928.