Attached to the Home Fleet, Onslow served mostly as an escort to Arctic Convoys. She also saw detached service in the Mediterranean during "Operation Harpoon" in 1942, and in the English Channel before and after the Normandy landings in mid-1944. Her most notable action was at the Battle of the Barents Sea in 1942, while escorting Convoy JW 51B to Russia. The convoy escorts held off attacks from the powerful German cruiserAdmiral Hipper, with Onslow being heavily damaged and her Captain, Robert St Vincent Sherbrooke severely injured.