After the outbreak of the First World War in August 1914, Queen, still part of the 5th Battle Squadron, initially served in the English Channel.

In late May 1915, Queen was withdrawn to reinforce the Italian fleet at the southern end of the Adriatic Sea after Italy joined the war on the side of the Allies.

[1] Due to slight differences between the last two members of the class—Queen and Prince of Wales—and the rest of the London-class ships, these vessels are sometimes referred to as the Queen class.

It was the first major public event attended by the couple since the end of the mourning period after Edward VII's accession the previous year.

She collided with the Greek merchant steamer SS Dafni at Dover on 1 February 1909, suffering no serious damage, and underwent a refit at Devonport in 1910–1911.

[a] In April 1914 she became 2nd Flagship, Rear Admiral, in the 5th Battle Squadron, Second Fleet, and was assigned duties as a gunnery training ship at Portsmouth.

[7] When the First World War began in August 1914, the 5th Battle Squadron was assigned to the Channel Fleet and based at Portland.

The German forces were attacking French positions to the east of Dunkirk, and they were in dire need of heavy artillery support.

Reports of an imminent German counterattack with armoured cruisers, which ultimately failed to materialize, led the British to send the battleships to guard against it in company with the Harwich Force.

[9][10] In March 1915, as the British and French fleets waging the Dardanelles campaign were preparing to launch a major attack on 18 March, the overall commander, Admiral Sackville Carden, requested two more battleships of the 5th Squadron, Implacable and Queen, to be transferred to his command in the expectation of losses in the coming operation.

By the time they arrived, the British had lost two battleships in the 18 March attack, prompting the Admiralty to send the last two ships of the 5th Squadron to join the fleet.

[11] Queen, Implacable, London, and Prince of Wales were transferred to the 2nd Detached Squadron, organised to reinforce the Italian Navy in the Adriatic Sea when Italy declared war on Austria-Hungary.

[12] Queen left Taranto and returned to the United Kingdom in April 1919 and was placed on the disposal list at Chatham Dockyard in May 1919.

She won a temporary reprieve from the scrapper's torch in June 1919 when she was removed from the list and attached to the Pembroke Establishment to serve as an accommodation ship.