Encounter was assigned to convoy escort and anti-submarine patrol duties in the Western Approaches, when World War II began in September 1939.

Late in the year, the ship was transferred to the Eastern Fleet at Singapore and spent several months in early 1942 on convoy escort duties under the control of American-British-Dutch-Australian Command (ABDACOM).

She was one of the Allied ships retasked to intercept Japanese invasion convoys during the Dutch East Indies Campaign in February 1942 and participated in the Battle of the Java Sea.

Encounter carried a maximum of 470 long tons (480 t) of fuel oil that gave her a range of 6,350 nautical miles (11,760 km; 7,310 mi) at 15 knots (28 km/h; 17 mph).

[4] Encounter, the sixth ship of that name to serve with the Royal Navy,[5] was ordered 1 November 1932, from Hawthorn Leslie & Company at Hebburn under the 1931 Naval Programme.

[6] Encounter and her sister ships were assigned to the 5th Destroyer Flotilla (DF) and accompanied the Home Fleet during its West Indies cruise between January and March 1935.

[7] Encounter was assigned to convoy escort duties in the Western Approaches Command for the first three months of the war before transferring to Scapa Flow and joining the Home Fleet.

[8] For the rest of the month and into May, Encounter escorted the aircraft carriers Ark Royal and Glorious and the battleships Warspite and Valiant in Norwegian waters.

[9] The following month, Encounter covered the destroyer Mashona on 2 June, as the latter ship recovered buoys from the wreck of the boom defence vessel Astronomer off Kinnaird Head.

She was refitted at Sheerness Dockyard from 20 June to 20 July and was then transferred to Gibraltar to join the 13th DF of Force H. En route, she escorted several troop ships and the aircraft carrier Argus.

[7] During Operation Hurry, Encounter and three other destroyers escorted Argus to a position south-west of Sardinia so the carrier could fly off her Hawker Hurricane fighters to Malta on 2 August.

[11] After escorting the carrier Furious to Freetown, Sierra Leone, and Takoradi, Ghana, in January 1941, Encounter rejoined Force H in time to participate in Operation Picket at the end of the month.

The British ships returned to Gibraltar on 4 February and began preparing for Operation Grog, a naval bombardment of Genoa, that was successfully carried out five days later.

While refitting in a drydock in Malta, Encounter was damaged by blast and splinters when a bomb detonated on the floor of the dock during an air raid on 29 April.

On 22 August, Force H, escorted by Encounter and four other destroyers, sailed to attack the airfield at Tempio Pausania, Sardinia, as a diversion for Manxman as she laid a minefield off Livorno, Italy.

[19] Encounter required a refit upon her arrival and was thus unavailable when Force Z sortied on 8 December on their ill-fated attempt to intercept the Japanese invasion convoys.

[22] 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 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.

[32] The following day, after making temporary repairs and refuelling, Exeter, Encounter and the American destroyer Pope were ordered to sail to Colombo, via the Sunda Strait.

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

[41] This humanitarian decision by Lieutenant Commander Shunsaku Kudō placed Ikazuchi at risk of submarine attack, and interfered with her fighting ability due to the sheer numbers of rescued sailors.