After a five-month fitting-out and sea trial phase she was declared battle ready. Wanklyn sailed for the Mediterranean Theatre on 10 December 1940. The vessel docked at Gibraltar before deploying for Malta. The entry of Italy into the war on 10 June 1940 had made the region a war zone. The Italian Navy ("Regia Marina") and Italian Air Force ("Regia Aeronautica") laid siege to the island. In September 1940 the Italian invasion of Egypt began a major land campaign. The objective of British submarine forces was to prevent the large Italian merchant fleets from supplying the Italian Army, and later the German Afrika Korps, in North Africa. Wanklyn now formed part of the 10th Submarine Flotilla in Malta under the command of Commander George Simpson. "Upholder" arrived there on 14 January 1941. While journeying to Malta, he provided distant cover for the supply fleet Operation Excess.