HMS Dorsetshire (pennant number 40) was a County-class heavy cruiser of the British Royal Navy, named after the English county, now usually known as Dorset.

Dorsetshire served initially in the Atlantic Fleet in the early 1930s, before moving to become the flagship of the Commander-in-Chief, Africa in 1933, and then to the China Station in late 1935.

In March 1942, Dorsetshire was transferred to the Eastern Fleet to support British forces in the recently opened Pacific Theatre of the war.

On 5 April, Japanese aircraft spotted Dorsetshire and her sister Cornwall while en route to Colombo; a force of dive bombers then attacked the two ships and sank them.

During the incident, some of her men initially refused to assemble for duty but after an hour and a half, the ship's officers had restored order and no further unrest troubled Dorsetshire during the mutiny.

[6] From 1–4 February 1937, Dorsetshire, the aircraft carrier Hermes and the cruiser Cumberland participated in an exercise to test the defences of Singapore against a hypothetical Japanese attack.

[8] In October, Dorsetshire—with other Royal Navy ships—was sent to South American waters in pursuit of the German heavy cruiser Admiral Graf Spee, which was attacking British merchant traffic in the area.

[9] Dorsetshire had just arrived in Simonstown, South Africa, from Colombo on 9 December, with orders to proceed to Tristan da Cunha and then to Port Stanley in the Falkland Islands to relieve Exeter.

[11] Exeter had been badly damaged in the battle with Admiral Graf Spee, and Dorsetshire escorted her back to Britain in January 1940, before returning to South American waters to search for German supply ships.

[8] On 11 February, her reconnaissance aircraft spotted the German supply freighter Wakama 12 nmi (22 km; 14 mi) off the coast of Brazil, which was promptly scuttled by her crew.

[12] Dorsetshire arrived on the scene shortly thereafter, picked up ten officers and thirty-five crewmen and sank Wakama to prevent her from being a navigational hazard.

[13][14] The following month, the President of Panama, Augusto Samuel Boyd, sent a formal complaint to the British government protesting against Dorsetshire's violation of the Pan-American Security Zone in the Wakama incident.

On 18 December she departed to join the search for the heavy cruiser Admiral Scheer, which had recently sunk the British refrigerator ship Duquesa in the South Atlantic.

[17] By May 1941, Dorsetshire had been assigned to Force H, along with the aircraft carrier Ark Royal, the battlecruiser Renown, and the light cruiser Sheffield.

[24] Historian Angus Konstam, however, writes that his research indicated a total of 116 saved, 86 on Dorsetshire (one of whom died), 25 on Maori, 3 rescued by U-74 and a further 2 picked up by the German weather ship Sachsenwald.

[25] Rodney, King George V and the destroyers Sikh, Zulu and Cossack had meanwhile begun to steam north-west to return to Scapa Flow.

Dorsetshire, Eagle and the light cruiser Newcastle left Freetown on 29 August, though they were unable to locate the German raider.

[27] On 4 November, Dorsetshire and the auxiliary cruiser Canton, were sent to investigate reports of a German surface raider in the South Atlantic but neither ship found anything.

[29] Dorsetshire was deployed in November, to join the search for the German commerce raider Atlantis, that had been attacking Allied shipping off the coast of Africa.

In March, Dorsetshire was assigned to Force A, which was commanded by Admiral James Somerville, with the battleship Warspite and the carriers Indomitable and Formidable.

The two British cruisers were attacked by a force of 53 Aichi D3A2 "Val" dive bombers 320 km (200 mi) southwest of Ceylon.