Aside from participating in the failed attempt to intercept the German ships that had bombarded Scarborough, Hartlepool and Whitby in late 1914, the Battle of Jutland in May 1916 and the inconclusive action of 19 August, her service during World War I generally consisted of routine patrols and training in the North Sea.

The turbines were rated at 27,000 shaft horsepower (20,000 kW) and were intended to give the battleships a speed of 21 knots (39 km/h; 24 mph).

The ships carried enough coal and fuel oil to give them a range of 6,730 nautical miles (12,460 km; 7,740 mi) at a cruising speed of 10 knots (19 km/h; 12 mph).

[4] The Orion class was equipped with 10 breech-loading (BL) 13.5-inch (343 mm) Mark V guns in five hydraulically powered twin-gun turrets, all on the centreline.

[8] Two flying-off platforms were fitted aboard the ship during 1917–1918; these were mounted on 'B' and 'X' turret roofs and extended onto the gun barrels.

[3] The last of the four Orions to be completed, Conqueror and her sister ships comprised the Second Division of the 2nd Battle Squadron (BS) of the Home Fleet.

The squadron departed for gunnery practice off the northern coast of Ireland on the morning of 27 October and the dreadnought Audacious struck a mine, laid a few days earlier by the German auxiliary minelayer SS Berlin.

On the evening of 22 November 1914, the Grand Fleet conducted a fruitless sweep in the southern half of the North Sea; Conqueror stood with the main body in support of Vice-Admiral David Beatty's 1st Battlecruiser Squadron.

They mustered the six dreadnoughts of Vice-Admiral Sir George Warrender's 2nd BS, including Conqueror and her sisters Orion and Monarch, and Beatty's four battlecruisers.

The Germans got the better of the initial exchange of fire, severely damaging several British destroyers, but Admiral Friedrich von Ingenohl, commander of the High Seas Fleet, ordered his ships to turn away, concerned about the possibility of a massed attack by British destroyers in the dawn's light.

Almost three weeks later, Conqueror participated in another fleet training operation west of Orkney during 2–5 November and repeated the exercise at the beginning of December.

On the night of 25 March, Conqueror and the rest of the fleet sailed from Scapa Flow to support Beatty's battlecruisers and other light forces raiding the German Zeppelin base at Tondern.

On 21 April, the Grand Fleet conducted a demonstration off Horns Reef to distract the Germans while the Imperial Russian Navy relaid its defensive minefields in the Baltic Sea.

[24] On 31 May, Conqueror, under the command of Captain Hugh Tothill, was the seventh ship from the head of the battle line after deployment.

During the first stage of the general engagement, the ship fired three salvos from her main guns at one battleship at 18:31 without visible effect.

She then shifted her fire to the crippled light cruiser SMS Wiesbaden, although the number of hits made, if any, is unknown.

They enforced strict wireless silence during the operation, which prevented Room 40 cryptanalysts from warning the new commander of the Grand Fleet, Admiral Beatty.

The British only learned of the operation after an accident aboard the battlecruiser SMS Moltke forced her to break radio silence to inform the German commander of her condition.

[28] The ship was present at Rosyth, Scotland, when the High Seas Fleet surrendered there on 21 November[29] and she remained part of the 2nd BS through 1 March 1919.