When World War II began in September 1939, the cruiser was assigned to patrol South American waters against German commerce raiders.

After repairs were completed the ship spent most of 1941 on convoy escort duties before she was transferred to the Far East after the start of the Pacific War in December.

Exeter was generally assigned to escorting convoys to and from Singapore during the Malayan Campaign, and she continued on those duties in early February 1942 as the Japanese prepared to invade the Dutch East Indies.

Later that month, she was assigned to the Striking Force of the joint American-British-Dutch-Australian Command (ABDACOM), and she took on a more active role in the defence of the Dutch East Indies.

The culmination of this was her engagement in the Battle of the Java Sea later in the month as the Allies attempted to intercept several Imperial Japanese Navy invasion convoys.

Consequently, the bridge was lowered (that of York being tall to give a view over the intended aircraft), and was of a streamlined, enclosed design that was incorporated into later cruisers.

The ship could carry 1,900 long tons (1,930 t) of fuel oil which gave her a range of 10,000 nautical miles (18,520 km; 11,510 mi) at 14 knots (26 km/h; 16 mph).

[5] The main armament of the York-class ships consisted of six BL eight in (203 mm) Mk VIII guns in three twin-gun turrets, designated "A", "B", and "Y" from fore to aft.

The bridge was rebuilt and enlarged to accommodate a second High-Angle Control System aft of the Director-Control Tower (DCT) on top of the bridge, her single four-inch AA guns were replaced with twin-gun mounts for Mark XVI guns of the same calibre and a pair of octuple mounts for two-pounder "pom-poms" were added abreast her aft superstructure.

In 1934 she was assigned, along with sister ship HMS York, to the 8th Cruiser Squadron based at the Royal Naval Dockyard in the Imperial fortress colony of Bermuda, on the America and West Indies Station.

[13] After re-commissioning in England on 29 December 1936, Exeter departed two days later, returning to Bermuda via St. Vincent, in the Cape Verde Islands, Montevideo and Punta del Este in Uruguay (meeting and exercising with her sister and the light cruiser HMS Ajax), Rio de Janeiro and Ceará in Brazil, Barbados (where the three cruisers joined the remainder of the squadron), and Tortola in the British Virgin Islands.

The ship's marines were withdrawn on 5 July after the situation in Trinidad had stabilised, and the heavy cruiser departed immediately for Balboa, Panama to continue its summer (Southern Hemisphere winter) cruise, which took her through the Panama Canal, up the Pacific coast of North America to HMCS Naden (the old Royal Naval Dockyard, Esquimalt), via San Diego, California.

Exeter's return trip took her to both coasts of South America before arriving at Bermuda on 28 March 1938 together with the light cruiser HMS Orion.

The ship, commanded by Captain Frederick Bell, was assigned to Force G to hunt for German commerce raiders off the eastern coast of South America on 6 October 1939.

The German ship straddled the British cruiser with her third salvo; shrapnel from the near misses killed the crew of the starboard torpedo tubes, started fires amidships and damaged both Supermarine Walrus seaplanes.

They knocked out 'A' turret, started a fire amidships that damaged the ship's fire-control and navigation circuits, and caused a seven-degree list with flooding.

In return, the cruiser had hit Admiral Graf Spee three times; one shell penetrated her main armour belt and narrowly missed detonating in one of her engine rooms, but the most important of these disabled her oil-purification equipment.

Several days later, unable to be repaired and apparently confronted by powerful Royal Navy reinforcements (including HMS Cumberland), the Admiral Graf Spee was scuttled by her captain in the harbour of Montevideo.

Then, on 10 March 1941, the day that Exeter was due to be recommissioned, Beckett died at Saltash Hospital from complications following exploratory surgery to repair poison gas injuries that he had received earlier in his career.

[27] Upon returning to the fleet, Exeter primarily spent time on 'working up' exercises,[28][29] however she also conducted several patrols in northern waters, one on which she stopped in Iceland to refuel.

Exeter then stayed on escort duty in the Indian Ocean (primarily off the coast of Africa)[34] and the northern Arabian Sea (where she visited Bombay, India) until 13 October.

On 13 February Allied reconnaissance aircraft spotted Japanese invasion convoys north of Bangka Island and the new commander of ABDA naval forces, Vice Admiral Conrad Helfrich of the Royal Netherlands Navy, was ordered to assemble the Allied Striking Force of Exeter and three Dutch and one Australian light cruisers at Oosthaven on the morning of 14 February.

[48] After they had arrived the following day, Doorman's entire force of five cruisers and nine destroyers departed Surabaya at 18:30 to patrol off Eastern Java in hopes of intercepting the oncoming invasion convoy which had been spotted earlier that morning.

The light cruisers and destroyers closed to ranges between 13,000 and 15,000 yards (12,000 and 14,000 m) and began firing Type 93 "Long Lance" torpedoes beginning at 16:03.

For some reason, two Japanese destroyers, Asagumo and Minegumo, continued to close before firing their torpedoes at 6,500 yards (5,900 m) and Encounter and Electra pulled out of line to counter-attack.

[60] The following day, after making temporary repairs and refuelling, the Exeter, escorted by Encounter and the American destroyer Pope, was ordered to steam to Colombo, via the Sunda Strait.

They departed on the evening of 28 February, but they were intercepted by the Japanese heavy cruisers Nachi, Haguro, Myōkō, and Ashigara, and by the destroyers Akebono, Inazuma, Yamakaze, and Kawakaze on the morning of 1 March.

[63] Exeter was able to reach a speed of 26 knots (48 km/h; 30 mph)[64] before the first hit on her detonated in her 'A', or forward, boiler room[54]: Item #44 & #45  and catastrophically knocked out all power around 11:20.

No direct hits were scored, but several more near-misses hastened the abandonment and scuttling of the vessel, and she was finished off by gunfire with the late arrival of the two IJN cruisers Ashigara and Myoko.

[71] The wreck was discovered and positively identified by a group of exploration divers specifically searching for Exeter aboard MV Empress on 21 February 2007.