Lancaster Castle was ordered on 19 December 1942 from Fleming and Ferguson, a Scottish shipbuilding company in Paisley, Renfrewshire.

In December, the group deployed to the Atlantic North West Approaches for convoy defence duties.

They continued in this role through to March 1945 when they were detached for Russian convoy defence with Home Fleet units.

A notable incident in this period was on 20 March 1945 when escorting convoy JW 65, they came under attack by six U-Boats, resulting in the loss of HMS Lapwing and the American merchant ships Horace Bushnel and Thomas Donaldson.

On 8 May, following the cessation of hostilities with Germany, the Lancaster Castle was released from convoy defence duties and deployed in home waters for the support of occupation forces and the collection of surrendered U-Boats.