Saipan was designated its target, and "Waller" began to bombard Japanese positions on that island. On the evening of 18 June, the warship received orders to give fire support in two areas to assist the marines in repelling an enemy tank attack. At 17:55, in company with "Pringle", she entered Magicienne Bay. "Waller" closed the beach to get a better view but was unable to distinguish any tanks—American or Japanese. At 17:58, all engines were stopped to give the watch a better look at the shore. Suddenly, three minutes later, enemy shore guns opened up on the two destroyers.