"Heywood L. Edwards" conducted her shakedown beginning 25 February off Bermuda and after gunnery exercises off the Maine coast departed to join the Pacific Fleet. Sailing from Boston, Massachusetts on 16 April, she transited the Panama Canal, stopped at San Diego, California and arrived at Pearl Harbor on 8 May. There "Edwards", took part in training manoeuvres with Task Force 52 (TF 52) under Vice Admiral Richmond K. Turner. The ships got underway from Pearl Harbor on 29 May for the Marianas with "Heywood L. Edwards" acting as screening unit for the transport group and during the initial landings on Saipan on 15 June the destroyer took up patrol station to seaward of the invasion beaches. From 21–30 June she approached the beaches to deliver fire support for the advancing Marines and continued that duty until 2 July. "Edwards" then joined the cruiser for the bombardment of Tinian, as part of the Marianas campaign.