Following shakedown off Bermuda, Key operated out of Norfolk, Virginia, training crews for destroyer escorts and patrolling the North Atlantic in quest of submarines. Clearing Hampton Roads 20 September, she escorted a convoy to Naples, Italy, then returned to New York 24 October. As a unit of CortDiv 76, she sailed from New York 10 November for duty with the U.S. 7th Fleet in the Southwest Pacific.
Transfer to the Pacific Fleet
Key arrived Hollandia, New Guinea, 27 December, and between 1 January 1945 and 6 February she made five escort runs from Hollandia to Leyte Gulf. On 9 February she began antisubmarine patrols east of Leyte Gulf; then she steamed to Mangarin Bay, Mindoro, 19 February for similar duty in the South China Sea. Returning to Leyte 14 March, the versatile destroyer escort operated out of Leyte Gulf and Polloc, Mindanao, screening ships en route to Lingayen Gulf, Luzon; Zamboanga, Mindanao; Jolo, Sulu Archipelago; and Legaspi and Manila, Luzon. After escorting a convoy of LSMs and LCIs to Davao Gulf 15 May, Key bombarded and destroyed an important Japanese patrol boat base at Piso Point before returning to Polloc on 17 May. After additional escort runs to Davao Gulf, Leyte Gulf, and Legaspi, Luzon, Key departed Manila Bay 11 June for duty in the Dutch East Indies. Arriving Morotai Island on 14 June, she screened Tawitawi-bound LCIs from 23–26 June before escorting a convoy on 28 June to a the following day with the amphibious force en route to the assault at Balikpapan, Borneo. While at Balikpapan on 7 July, Key rescued a survivor from an LCM sunk by a mine in the harbor. She patrolled for enemy submarines until 22 July when she sailed via Morotai for Leyte Gulf, arriving 4 August.
End-of-war operations
Operating out of Leyte after the end of hostilities, Key steamed on antisubmarine patrols east of Leyte from 22 to 31 August and escorted a convoy to Ulithi, Western Carolines before sailing to Manila on 8 September. Between 18 September and 23 November she made two escort runs from Manila Bay to Okinawa to support American occupation operations in Japan. Clearing Manila Bay on 25 November, she embarked homebound veterans on 27 November at Guiuan, Samar and departed the next day for the United States.
