On 31 May, the warship stood out of Pearl Harbor with Task Group 52.17 (TG 52.17) and set a course—via Kwajalein in the Marshall Islands—for the invasion of Saipan in the Marianas. For that operation, "Yarnall" was assigned to Fire Support Group 1 under Rear Admiral Jesse B. Oldendorf. When her task group began its pre-landing bombardment of Saipan on 14 June, "Yarnall" screened "Cleveland" (CL-55) and "Montpelier" (CL-57) and managed to add 148 rounds of her own 5 inch shells to the effort. On 15 June, the day of the assault, she continued to screen "Cleveland" and, on the following day, carried out her first call fire mission—a dual-purpose action to help repulse an enemy counterattack and to destroy a bothersome pillbox.