Commissioned November 25, 1940, at Collingwood, she arrived at Halifax on December 11 for completion and was assigned to Halifax Local Defence Force until May 23, 1941. Orillia sailed that day for St. John's to become one of the seven charter members of the NEF, and for the balance of the year escorted convoys between St. John's and Iceland. In September 1941, she was escort to convoy SC.42, which lost 18 ships. She arrived at Halifax December 24 for a refit, upon completion of which on March 22, 1942, she joined EG C-1, leaving St. John's April 3 with SC.77 for Londonderry. On her arrival she was sent to Tobermory for three weeks' workups, then returned to the "Newfie-Derry" run until January, 1944. Orillia took part in major battles around convoys SC.94, which lost 11 ships in August, 1942 and ON.137 that October, which lost only 2 ships despite being heavily attacked. She was a member of EG C-2 from November, 1942 to May, 1944, when she joined EG C-4 following two months' refit at Liverpool, N.S. She left Londonderry for the last time on January 16, 1944, to commence a long refit, again at Liverpool, which included the lengthening of her fo'c's'le. This refit was completed on May 3, but further repairs were completed at Halifax late in June. She arrived in Bermuda on June 29 for three weeks' workups, on her return joining EG W-2, Western Escort Force, for the duration of the war. Paid off on July 2, 1945, at Sorel, she was broken up at Hamilton in 1951.
Focsle Extended, Liverpool, NS, 3 Mar 44