This ship introduced Krupp Cemented armour which allowed a considerable saving in weight, 25.4 mm of Krupp armour was equivalent to 66 mm of iron.

HMS Canopus was a pre-Dreadnought battleship, and the only one of her class to serve in the Mediterranean fleet instead of the China station. In 1906 she returned to the Channel fleet and also went into refit to receive Fire control. Further refitting was done while with the reserve at Portsmouth with reduced crew in 1908 – 09. On her return to the fleet she served as the parent ship for the 4th Division at the Nore and with the home fleet from May 1912 and again refitted at Chatham dockyard.

In 1913 she was stationed at Pembroke and at the outbreak of the Great War joined the 8th battle squadron of the Channel fleet. Soon after she was sent to the Falkland Islands to join Cradock’s fleet, however owing to reported engine problems she was not at the Battle of Coronel.

Prior to the Battle of the Falklands (8th Dec. 1914) she was beached at Stanley as a defence for the port. In 1915 she was sent to the Mediterranean to support the Dardanelle's expedition, received damage by Turkish Gun fire on the 28th April and 2nd May 1915. During May 1916 she returned to Chatham Docks and on her return became the guard ship on the East Coast. Sent to Devonport in 1918 where she became a accommodation ship until finally being sold to the breakers in 1920.