Whilst working up, 818 and 824 Squadrons flew aboard in April 1943. 818 Squadron had nine Fairey Swordfish torpedo bombers and 824 Squadron had six. 887 Squadron, with nine Supermarine Seafire IIC fighters was also embarked during this time. In late May, "Unicorn" escorted Convoy MKF 15 to Gibraltar while carrying a number of Royal Air Force Bristol Beaufighters that she off-loaded there. She escorted the returning convoy back to the Clyde in early June. Together with the aircraft carrier , the ship made a sweep towards the Norwegian coast as part of Operation Governor, a diversion for the Allied landings in Sicily in early July. For this operation, 887 Squadron was replaced by 800 Squadron with Hawker Sea Hurricanes.