"Rheinland" carried a main battery of twelve SK L/45 guns in an unusual hexagonal configuration. Her secondary armament consisted of twelve SK L/45 guns and sixteen SK L/45 guns, all of which were mounted in casemates. The ship was also armed with six submerged torpedo tubes. One tube was mounted in the bow, another in the stern, and two on each broadside, on both ends of the torpedo bulkheads. The ship's belt armor was thick in the central portion of the hull, and the armored deck was thick. The main battery turrets had thick sides, and the conning tower was protected with of armor plating.