She headed for the Southwest Pacific on 27 November via the Panama Canal and the Society Islands. En route, on 13 January 1943 Niagara was reclassified as the Navy's first motor torpedo boat tender and redesignated AGP–1. Niagara arrived at Nouméa, New Caledonia on 17 January 1943 and began tending Motor Torpedo Boat Division 23, Squadron 8. She sailed with the division on the 27th and reached her base at Tulagi, Solomon Islands on 17 February. In the ensuing months, she tended the motor torpedo boats running security patrols off Guadalcanal.
