HMS UNRIVALLED (P45) (Lt. H B Turner, RN) departed Malta on 22 December 1942 for her 5th war patrol (3rd in the Mediterranean). She was ordered to patrol between Kerkenah and Kuriat. On 25 December, she attacked a convoy made up of the Italian sailing vessel Pasquale Costa and the German landing barges F479 and F546 off Mahdia, Tunisia. Following the attack F479 dropped 4 depth charges.  During this action, one of the gun crew was hit by the enemy and was seriously wounded. Course was then set to return to Malta to put him ashore for treatment but he died a few hours later.

On 2 March 1943, UNRIVALLED departed Malta for her 8th war patrol (6th in the Mediterranean). She was ordered to perform a special operation (beach reconnaissance) for the upcoming Operation HUSKY (Sicily landings). At 2123 on 7 March, UNRIVALLED launched a folbot with a crew of two for a beach reconnaissance. The folbot failed to return. The launch position was approximately 36°40'N, 14°53'E. At 1953 on 8 March 1943 a folbot with a crew of two was launched to search for the crew of the folbot that had been launched the previous evening. This folbot and her crew also failed to return. These two men were captured by Italian coast guards, but it is assumed that the pair launched the previous evening were drowned.