Between 11 May and 24 June 1942, "Sahib" underwent a period of training, then departed for her first war patrol. She was ordered to operate off Northern Norway and protect the Arctic Convoys PQ 17 and QP 13 to and from northern Russian ports. On 11 July, "Sahib" fired six torpedoes at the German submarine but missed, then ended her patrol in Lerwick the next day.