During the first part of June "Hailey" took up screening and patrol duties east of Saipan in support of the Marianas operations. She sortied from Eniwetok 1 July with Admiral Weyler's Battleship Division 3 for the pre-invasion bombardment and softening up of Guam, then joined Admiral Conolly's Southern Attack Force for the capture of Guam (21 July–10 August 1944) retiring to Eniwetok 9 August. The remainder of August and September "Hailey" screened a group of escort carriers furnishing air support for the seizure and occupation of Peleliu, Ngesebu, and Anguar Islands in the Palaus.