The gun turrets were protected by Krupp armour, on their faces and 10 inches on their backs, with roofs 2 to 3 inches thick. The Krupp armour of the barbettes was 12 inches thick above the main deck, but 10 inches on the face and sides and 6 inches on the rear below it. The casemates were protected by 6 inches of Krupp armour. The thicknesses of the mild steel decks ranged from . The walls of the forward conning tower were 10 inches of Harvey armour with a roof and the aft conning tower had three inches of nickel steel.