11 Apr, 1940
HMS Penelope (Capt. G.D. Yates, RN) entered Vestfjord to support the attack of British destroyers against the German destroyer flotilla of Commodore Bonte at Narvik, but on the way in the cruiser ran aground on rocks off Fleinver and was badly damaged. She was towed clear by the British destroyer HMS Eskimo (Cdr. St.J.A. Micklethwait, DSO, RN).
While executing temporary repairs, she was attacked by German bombers, which obtained 4 near-misses to port, within 13 metres of the hull, exacerbating the damage already sustained by hitting the rocks. Penelope eventually reached the Tyne but was under repairs until 7 July 1941.

21 Oct, 1940
HMS Penelope arrives at Malta to join Force "K".

9 Nov, 1941
The British Force K, made up of the British light cruisers HMS Aurora (Capt. W.G. Agnew, RN) and HMS Penelope (Capt. A.D. Nicholl, RN) and the British destroyers HMS Lance (Lt.Cdr. R.W.F. Northcott, RN) and HMS Lively (Lt.Cdr. W.F.E. Hussey, DSC, RN), intercept an Italian convoy about 130 nautical south-west off Calabria in approximate position 37º08'N, 18º09'E. The Italian convoy is bound from Naples to Tripoli.

In the resulting battle the Italian destroyer Fulmine is sunk as well as the German transports Duisburg (7389 GRT) and San Marco (3113 GRT), the Italian transports Maria (6339 GRT), Sagitta (5153 GRT) and Rina Corrado (5180 GRT), and the Italian Conte di Misurata (5014 GRT) and Minatitlan (7599 GRT). The Italian destroyers Grecale and Euro are damaged. (see map)

24 Nov, 1941
The British Force K, made up of the British light cruisers HMS Aurora (Capt. W.G. Agnew, RN) and HMS Penelope (Capt. A.D. Nicholl, RN) and the British destroyers HMS Lance (Lt.Cdr. R.W.F. Northcott, RN) and HMS Lively (Lt.Cdr. W.F.E. Hussey, DSC, RN), intercept an Axis convoy about 100 nautical miles west of Crete. The Axis convoy is bound from the Aegean to Bengasi.

The two German tansports in the convoy Maritza (2910 GRT) and Procida (1842 GRT) are both sunk by HMS Penelope and HMS Lively dispite the presence of the Italian torpedo boats Lupo and Cassiopea.

1 Dec, 1941
Acting on an ULTRA intercept, a British force sailed from Malta in the evening of 30 November with the British light cruisers HMS Neptune (Capt. R.C. O'Conor, RN), HMS Aurora (Capt. W.G. Agnew, RN), HMS Ajax (Capt. E.D. McCarthy, DSO and Bar, RN), HMS Penelope (Capt. A.D. Nicholl, RN) and the British destroyers HMS Kimberley (Cdr. J.S.M. Richardson, DSO, RN), HMS Kingston (Cdr. P. Somerville, DSO, DSC, RN) and HMS Lively (Lt.Cdr. W.F.E. Hussey, DSC, RN).
At 0330 hrs of 1/12 the British intercept and sink the Italian transport Adriatico (1976 GRT) then proceed towards the Lybian coast.
At a point 60 nautical miles north-north-west of Tripoli, Libya, Penelope, Aurora and Lively intercept a small convoy consisting of the Italian oiler Iridio Mantovani (10540 GRT) escorted by the Italian destroyer Alvise da Mosto (2125 tons) and sink both.

19 Dec, 1941
While on their way to intercept an Italian convoy bound for Tripoli the British Force K (light cruisers HMS Neptune (Capt. R.C. O'Conor, RN), HMS Aurora (Capt. W.G. Agnew, RN), HMS Penelope (Capt. A.D. Nicholl, RN) and the destroyers HMS Kandahar (Cdr. W.G.A. Robson, DSO, DSC, RN, HMS Lance (Lt.Cdr. R.W.F. Northcott, RN), HMS Lively (Lt.Cdr. W.F.E. Hussey, DSC, RN) and HMS Havock (Lt. G.R.G. Watkins, DSC, RN) ran into an newly laid Italian minefield. HMS Neptune and HMS Kandahar sank while HMS Aurora was badly and HMS Penelope was lightly damaged. HMS Aurora was patched up at Malta before returning home for repairs at Liverpool from April to June 1942. HMS Penelope was repaired at Malta but was bombed on 26 March 1942 while still under repair. She left Malta on 8 April 1942 for full repairs at the New York Navy Yard in the USA. These repairs were completed in September 1942.

19 Mar, 1942
In the aftermath of the Battle of the Syrte, attempted towing the damaged Breconshire (9776 GRT) into port, but the freighter sank before reaching safe waters.

20 Mar, 1942
In the period between 20-30 March 1942, Axis air attacks on malta were extremely heavy. Ammunition expenditure by Penelope during the 10-day period amounted to 6.500 rounds of 102 mm (4") and over 75.000 rounds of small calibre. She sustained so much splinter damage top earn the nickname "Pepperpot.
Folowing a particularly heavy attack on 26 March, it was decided to send her to the US for repairs. She sailed from Malta on 8 April for New York Navy yard and was under repairs until 1 September. Returned to the Med in early 1943 and was assigned to Force "Q", operating out of Bone, Algeria.

Jun, 1943
During the first week of June bombarded Pantelleria and Lampedusa islands, in the Sicilian Channel, on 11 June supported the Pantelleria landings.

Aug, 1943
Deployed in support of Operation "Husky", the sicilian landings.

9 Sep, 1943
Deployed in support of the Salerno landings, after the announcement of the Italian Armistice ferried troops to Taranto and in October moved to operate in the Aegean.

7 Oct, 1943
The Britsh light cruisers HMS Penelope (Capt. G.D. Belben, DSC, RN) and HMS Sirius (Capt. P.B.W. Brooking, DSO, RN) and the British destroyers HMS Faulknor (Capt. A.K. Scott-Moncrieff, DSO, RN) and HMS Fury (Lt.Cdr. T.F. Taylor, RN), north of Astipalea (Stampalia) in the Dodecanese, attacked a German convoy consisting of the auxiliary submarine chaser UJ 2111 (667 tons, former Italian Tramaglio), cargo Olympus (5216 GRT) and 7 MFPs, sinking all but one MFP.
On the return leg of the mission, the British were repeatedly attacked by German planes while transiting Karpathos Strait (Scarpanto).

Dec, 1943
Left the Med for a short period of time to hunt down blockade runners in the Bay of Biscay.

Jan, 1944
Deployed in support of the Anzio landings.