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.

When her task group began its pre-landing bombardment of Saipan on 14 June, Yarnall screened Cleveland (CL-55) and Montpelier (CL-57) against attack, and also fired 148 five inch shells.

On the 17th, as a result of the submarine sightings of the Japanese fleet moving toward the Marianas, Yarnall and 20 other destroyers were detached from direct support for the invasion and ordered to screen the fast carriers.

She engaged the attacker with three guns of her main battery; as the plane closed on the destroyer's port quarter it exploded and splashed into the sea, Yarnall's first victory.

About five hours after that attack, the ship received word of the first of the four large air raids launched by the Japanese Mobile Fleet to attempt to break up the American invasion force off Saipan.

At about 10:45, Yarnall and Stockham encountered the first carrier-based aircraft of the battle when five Aichi D3A "Val" dive bombers peeled off to attack the two picket destroyers.

American carrier search planes found the enemy late in the day, and TF 58 launched air strikes from extreme range.

The following day, the destroyer returned to the coast of Saipan to resume call fire missions supporting the troops fighting ashore.

There, she resumed patrol and antisubmarine screening duties and kept at such tasks until the 25th when she moved inshore to provide gunfire support for the troops occupying Tinian.

On 29 August she left the anchorage in company with TG 38.2 for an aerial sweep of the Philippine Islands in preparation for the invasion of the archipelago at Leyte.

On the latter day, Yarnall sortied with the entire Fast Carrier Task Force for a three-day aerial sweep of Japanese air bases on Formosa.

After successfully completing that mission, TF 38 made a fueling rendezvous on 30 and 31 October and then resumed its duty pounding enemy installations on Luzon.

In December, she returned to the Philippines with TG 38.1 to support the landings on the island of Mindoro and to continue the pressure on Japanese air forces based on Luzon.

That night, Yarnall accompanied the fast carriers through Bashi Channel into the South China Sea to begin a series of raids on Japan's inner defense line.

The task force exited the South China Sea via Balintang Channel and then hit Formosa and the Nansei Shoto on 21 January.

On 10 February, Yarnall left Ulithi with TF 38 to attack the Japanese home islands for the first time since the Halsey-Doolittle Raid and to provide strategic cover for the assault on Iwo Jima.

She stood out of Ulithi on 5 April and steamed via Pearl Harbor to the Mare Island Navy Yard where she underwent repairs until 2 July.

She was present in Tokyo Bay on 2 September when Japanese officials signed the surrender document on board Missouri (BB-63) and remained in the Far East supporting minesweeping operations until the end of October.

For the most part, Yarnall served in the screen of TF 77, the carrier task force, though on occasion she moved close to the coast of Korea to provide gunfire support for the United Nations troops operating ashore.

A month and a day later, she departed San Diego; set a course via Pearl Harbor and Midway for the western Pacific; and arrived in Yokosuka on 6 August.

Again, her duties consisted of screening TF 77 carriers and providing bombardment services, frequently at the besieged port city of Wonsan.