The ship returned to the Hawaiian Islands for further operational training in preparation for the upcoming conquest of the Marianas. Assigned to Task Group 52.4 (TG 52.4), "Wadleigh" arrived off Roi Island in the Marshalls on 10 June, five days before D-Day for the invasion of Saipan Island. The day before the first landings, the warship closed Saipan and commenced fire early in the morning, beginning her part in the operations designed to "soften up" the enemy defenses.