The ship was armed with a single Mk IX naval gun, two depth charge throwers and two depth charge rails, and could carry 40 depth charges.
Mallow was built by the firm of Harland and Wolff at Belfast, Northern Ireland under shipyard number 1065, and was ordered on 19 September 1939, laid down on 14 November 1939, launched on 22 May 1940, and commissioned on 2 July 1940.