6 Dec, 1939
During the night of 6/7 December 1939 the German destroyer Z 12 escorted by her sister ship Z 10 was on an offensive mining operation off Cromer. At 0255hours, just 15 minutes after the lay had been completed, the German ships sighted the British destroyers HMS Juno and HMS Jersey about 8000m away. The Germans turned to a parallel course and by 0310hours had closed range to 4,600m while remaining undetected themselves. Z 10 fired three torpedoes at Juno, the lead British ship while Z 12 sent four more torpedoes at Jersey. Z 10's salvo missed, but Z 12 scored with one torpedo. The blow started a large fire and caused damage that required ten months to repair. Juno turned back to assist Jersey, making smoke; apparently the British believed a submarine had attacked them. The Germans still had the advantage of surprise and fired at least five more torpedoes, but then they decided to break off the action and return for home. HMS Jersey was under repair until 23 September 1940.

10 Oct, 1940
HMS Jersey set off a mine when leaving the Humber and sustained some damage, repairs were carried out in the docks in London. Jersey arrived at Plymouth on the 13th October.

6 Feb, 1941
British raid on Genua.

Force H (Vice Admiral Somerville) left Gibraltar on 6 February 1941. The battlecruiser HMS Renown, battleship HMS Malaya, aircraft carrier HMS Ark Royal, light cruiser HMS Sheffield and the destroyers HMS Fearless, HMS Foxhound, HMS Foresight, HMS Fury, HMS Encounter and HMS Jersey left Gibraltar to the west with convoy HG-53. This was done to fool German and Italian observers in Spain. In the meantime 4 destroyers HMS Duncan, HMS Isis, HMS Firedrake and HMS Jupiter left Gibraltar and steamed to the east to conduct a anti-submarine sweep. During the night Force H reversed course and passed Gibraltar on a westerly course back into the Mediterranean. There they were joined by the 4 destroyers that conducted the anti-submarine sweep.

On 8 February the Italian fleet left port and steamed south after they received reports of British carrier aircraft south of the Balearen. The Italians thought that there was another convoy to Malta.

Early in the morning of 9 February Renown, Malaya and Sheffield bombarded the Italian city of Genua. In the harbour 4 ships were sunk and 18 were damaged. Also the city itself was damaged.

The Italian fleet turned around and tried to intercept the British ships but due to the bad weather this failed.

In the meantime Ark Royal's arcraft raided Livorno and mined the harbour of La Spezia.

Force H safely returned to Gibraltar on 11 February.