Allentown was laid down on 23 March 1943, at the Froemming Brothers, Inc., shipyard in Milwaukee, Wisconsin, under a Maritime Commission contract (MC hull 1477).

Launched on 3 July 1943, sponsored by Miss Joyce E. Beary, she was moved to New Orleans, Louisiana, where she fitted out and was commissioned on 24 March 1944.

On 9 March, Allentown joined the escort of a Ulithi-bound convoy on the first leg of her voyage back to the United States.

On 15 July 1945, EK-9 departed Cold Bay in company with nine of her sister ships – EK-1 (ex-Charlottesville), EK-2 (ex-Long Beach), EK-3 (ex-Belfast), EK-4 (ex-Machias), EK-5 (ex-San Pedro), EK-6 (ex-Glendale), EK-7 (ex-Sandusky), EK-8 (ex-Coronado), and EK-10 (ex-USS Ogden (PF-39)) – bound for Petropavlovsk-Kamchatsky in the Soviet Union.

[5] In February 1946, the United States began negotiations for the return of ships loaned to the Soviet Union for use during World War II.

[6] Reverting to her former name, Allentown remained at Yokosuka, laid up in the Pacific Reserve Fleet, until 2 April 1953 when she was loaned to Japan.

[7] The United States struck her name from the Navy list on 1 December 1961 and transferred her to Japan on a permanent basis on 28 August 1962.