The ship helped to briefly seize four Swedish warships en route from Italy to Sweden in June 1940 in what became known as the Psilander affair and resumed her role of convoy escort after their release in July.

[7] The primary armament of the Tribal-class was eight quick-firing (QF) 4.7-inch (120 mm) Mark XII guns in four twin-gun mounts, one pair each fore and aft of the superstructure, designated 'A', 'B', 'X', and 'Y' from front to rear.

[12] To increase the firing arcs of the AA guns, the rear funnel was shortened and the mainmast was reduced to a short pole mast.

[16] The ship was ordered on 19 June 1936 from Parsons, but her hull was subcontracted to Vickers-Armstrong and was laid down on 5 August at the company's High Walker, Newcastle upon Tyne, shipyard.

Launched on 3 September 1937, Mashona was completed on 30 March 1939 and commissioned on 1 April at a cost of £341,108 which excluded weapons and communications outfits furnished by the Admiralty.

[17] When Great Britain declared war on Nazi Germany on 3 September 1939, Mashona and the bulk of the Home Fleet were unsuccessfully patrolling the waters between Iceland, Norway and Scotland for German blockade runners.

The 2nd Cruiser Squadron, including Mashona, was already at sea when the submarine Spearfish, on patrol in the Heligoland Bight, was badly damaged by German depth charges on 24 September.

By the time the British realised that the battleship had been torpedoed and Mashona became the first ship to search for the submarine, some two hours had passed and U-47 had reached the open sea.

Following the sinking of the armed merchant cruiser Rawalpindi on 23 November by the German battleships Scharnhorst and Gneisenau off Iceland, Mashona and the rest of the Home Fleet hunted the enemy ships, but heavy weather allowed them to evade their pursuers and return to Germany.

The ship spent the next several months on convoy escort and patrol duties and Commander William Selby relieved McLaughlin on 23 January 1940.

[20] After refuelling at Scapa Flow the following day, Mashona, five of her sisters and two light cruisers departed on the evening of 11 April, arriving off Stadlandet the following morning.

The following morning they were ordered north to the Namsos area to examine its suitability for an Allied landing and to coordinate with local Norwegian forces.

The Admiralty ordered that the 148th Infantry Brigade, already at sea, to be diverted to the anchorage at Lillesjona; its troopships arrived there at dawn on 16 April and began transferring their troops to the destroyers after they had completed refuelling.

[22] Mashona, Tartar and their sister Maori were ordered on 19 June 1940 to seize four Swedish destroyers that had been purchased from Fascist Italy and were on their delivery voyage, citing the right of angary, which allows for the taking of neutral property to prevent its use by the enemy.

Upon its completion on 5 October, Mashona was assigned escort duties in the Western Approaches and rescued survivors from the torpedoed cargo liner SS Rotorua on 11 December.

[24] On 22 May 1941 the ship formed part of the escort for Rodney and the ocean liner MV Britannic as they set sail for Halifax, Canada.

A Heinkel He 111 of the first group of Bomber Wing 28 (I/Kampfgeschwader 28) hit Mashona with a single bomb in the forward boiler room that caused severe flooding and killed 46 men.

The floating hulk was finally sunk off the coast of Galway, Ireland, at 52°58′N 11°36′W / 52.967°N 11.600°W / 52.967; -11.600 by shells from a pair of Canadian destroyers that arrived that afternoon.