The ship was built at the Chatham Dockyard; her keel was laid down in March 1895, her completed hull was launched in September 1896, and she was commissioned into the fleet in April 1898.

One of the oldest battleships in the Royal Navy when the First World War broke out, she served as a guard ship at various regions around Northern England until late 1915.

Her propulsion system consisted of two 3-cylinder triple-expansion steam engines powered by eight coal-fired, cylindrical fire-tube Scotch marine boilers.

[2] The ship was armed with a main battery of four BL 12-inch (305 mm) Mk VIII guns in twin-gun turrets, one forward and one aft.

[1] The barbettes for the main battery were protected with 14 in (356 mm) of armour, and the conning tower had the same thickness of steel on the sides.

[2] She commissioned at Chatham for service in the Fleet Reserve on 15 April 1898, Captain Sir Richard Poore in command.

This resulted in a violent riot by Cretan Turks against British soldiers, sailors, and Christian civilians in Candia on 6 September 1898, which in turn prompted a flood of reinforcements to the town by the International Squadron.

[3] Captain Francis John Foley was appointed in command on 24 March 1902,[6] and the following June she was the lead ship in a coronation fête at Gibraltar.

She underwent a refit in 1912, and later that year was transferred to the 3rd Fleet and participated in manoeuvres as Flagship, Vice Admiral, 7th Battle Squadron.

[3][notes 1] In late July 1914, the Royal Navy began a precautionary mobilisation, as war seemed imminent.

At first, it was planned that Illustrious would pay off to provide crewmen for the new dreadnought battleship HMS Erin, but instead she was placed in full commission to serve as a guard ship for the Grand Fleet once the First World War began in August 1914.

[3][notes 2] Illustrious paid off at Grimsby on 26 November 1915 to be converted to a disarmed harbour ship; two of her 12-inch (305-mm) guns were re-used in the Tyne Turrets.