"Itsukushima" had a steel hull with 94 frames constructed of mild steel, and a double bottom, divided into waterproof compartments, with the area between the bulkheads and armor filled with copra. The bow was reinforced with a naval ram. The vital equipment, including boilers and ammunition magazines, were protected by hardened steel armor, as were the gun shields. The main armament consisted of one breech-loading Canet gun mounted in the bow of the ship, which could fire armor-piercing or explosive shells at an effective range of . The maximum rate of fire was two rounds per hour, and the ship carried 60 rounds. Secondary armament consisted of eleven QF 4.7 inch Gun Mk I–IV Armstrong guns, with a maximum range of and maximum rate of fire of 12 rounds/minute. Ten were mounted on the gun deck, five to each side, with the eleventh gun located on the upper deck of the fantail. Each gun was equipped with 120 rounds. Tertiary protection was by six QF 6 pounder Hotchkiss mounted in sponsons on the upper deck, with a maximum range of and rate of fire of 20 rounds/minute. Each gun had 300 rounds. In addition, eleven QF 3 pounder Hotchkiss were mounted at various locations, with range of rate of fire of 32 rounds/minute and 800 rounds per gun. Each ship in the class also had four torpedo tubes, three in the bow and one in the stern, with a total of 20 torpedoes carried on board. The weight of all of this weaponry led to the design becoming dangerously top-heavy, and armor was sacrificed in an effort to reduce weight.