Sentry was laid down on 16 May 1943 by the Winslow Marine Railway and Shipbuilding Co., Seattle, Washington; launched on 15 August 1943 sponsored by Miss Nanette L. Pratt, and commissioned on 30 May 1944.

After shakedown, Sentry sailed from San Francisco, California, on 28 August 1944 and joined the U.S. 7th Fleet at Manus on 6 October for the Leyte invasion.

On 13 February, Sentry 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.

Sentry continued sweeping in Manila Bay through 19 February, and her division earned a Navy Unit Commendation for the operation.

After overhaul at Subic Bay, Sentry departed the Philippines on 8 September and arrived at Sasebo Japan, on 20 October, having accepted the surrender of the Japanese army garrison of Shan Zaki in the Ryukyus while en route.