After shakedownScrimmage sailed from San Francisco, California, on 11 June 1944 for Pearl Harbor. After a convoy voyage to Enewetak Atoll and back, she helped sweep an old United States minefield in the French Frigate Shoals northwest of Oahu between 6 and 15 August. She reported to the 7th Fleet at Manus on 20 September for the Leyte invasion. On 20 October, she joined her division, Mine Division 34, off the Leyte beaches for a four-day sweep of the main transport channel and then anchored with the transports to provide anti-aircraft support.
Searching for survivors
Between 27 and 31 October, she helped search for survivors at the scene of the Battle off Samar, where a few American escort carriers and their screen had withstood the attack of a superior Japanese force. For the next month, she carried out local patrols and sweeps around Leyte, and made a convoy voyage to Manus and back.
Scrimmage participated, with her divisions in most of the subsequent landings in the Philippines. She carried out pre-invasion sweeps at Ormoc Bay on 6 December 1944, Mindoro Island on 14 December, Lingayen Gulf on 6 January 1945, and Zambales and Subic Bay on 29 and 31 January. For all but the Ormoc assault, she remained on the scene after the initial landings, helping extend the mineswept areas and providing antisubmarine and antiaircraft protection to the transports. Few mines were encountered, but kamikaze resistance was intense, and the ships saw much antiaircraft action.
Under fire from Japanese shore batteries
On 13 February, Scrimmage and her division began pre-invasion sweeps in Manila Bay in preparation for the landings at Mariveles and Corregidor. While sweeping off Corregidor on the 14th, the minesweepers came within 5,000 yards of the island and were repeatedly straddled by Japanese fire before supporting ships silenced the enemy's guns. Scrimmage continued sweeping in Manila Bay through 19 February, and her division earned a Navy Unit Commendation for the operation. During the next two and one-half months, Scrimmage carried out various local sweeps in support of fighting in the Philippines, the most notable being a pre-assault sweep for the landings at Legaspi, Luzon on 1 April, and an 8-day sweep in the Sulu Sea off Palawan beginning on 22 April. On 9 May, the ship arrived at Morotai to prepare for operations in the Dutch East Indies.
Between 7 and 18 June, Scrimmage supported the landings at Brunei Bay, Borneo. During the operation, the minesweepers came under fire from shore batteries and one ship,, was sunk by a mine on 8 June. On completion of the operation, Scrimmage returned to Subic Bay for emergency engine repairs, arriving on 21 June.
End-of-war activity
The minesweeper left the Philippines on 6 September and arrived at Nagoya, Japan, on 9 October, having weathered three typhoons en route. Between 16 October and 3 December, she swept Japanese minefields in the approaches to the Inland Sea and in Tsushima Strait. On 9 December she sailed from Sasebo for home.