The engines were rated at 28,000 metric horsepower (27,617 ihp; 20,594 kW) and were capable of producing a top speed of 20.8 knots (38.5 km/h; 23.9 mph).

[8] The ship's secondary battery consisted of fourteen 15 cm (5.9 in) SK L/45 guns, all of which were mounted in casemates in the side of the upper deck.

Admiral Alfred von Tirpitz, the State Secretary of the Navy, gave the contract to Schichau before the 1909 budget had been approved, and the shipbuilder began stockpiling materials to build the ship.

[12] After launching, the incomplete ship was transferred to Kiel for fitting out, including completion of the superstructure and the installation of armament, until August 1911.

[1] Named for the Duchy of Oldenburg in northern Germany, the ship was commissioned into the High Seas Fleet on 1 May 1912, just over three years after work commenced.

[15] The annual summer cruise to Norway began on 14 July 1914,[16] despite the rising international tensions following the assassination of Archduke Franz Ferdinand of Austria.

[17][e] During the last peacetime cruise of the Imperial Navy, the fleet conducted drills in the Skagerrak before proceeding to the Norwegian fjords on 25 July.

That evening, the German battle fleet of eight pre-dreadnoughts and twelve dreadnoughts, including Oldenburg and her three sisters, came to within 10 nmi (19 km; 12 mi) of an isolated squadron of six British battleships.

As a result, Kaiser Wilhelm II removed Ingenohl from his post and replaced him with Admiral Hugo von Pohl on 2 February.

[13] The assault force included the eight I Squadron battleships, the battlecruisers Von der Tann, Moltke, and Seydlitz, several light cruisers, 32 destroyers and 13 minesweepers.

The dreadnoughts Nassau and Posen were detached on 16 August to escort the minesweepers and to destroy Slava, though they failed to sink the old battleship.

[13] On 23–24 October, the High Seas Fleet undertook its last major offensive operation under the command of Admiral Pohl, though it ended without contact with British forces.

[13] Weakened by hepatic cancer and unable to carry out his duties, he was replaced by Vice Admiral Reinhard Scheer in January.

[28] Scheer proposed a more aggressive policy designed to force a confrontation with the British Grand Fleet; he received approval from the Kaiser in February.

At this point, Scheer, who had been warned of the sortie of the Grand Fleet from its base in Scapa Flow, also withdrew to safer German waters.

The opposing ships began an artillery duel that saw the destruction of Indefatigable, shortly after 17:00,[33] and Queen Mary, less than half an hour later.

[34] By this time, the German battlecruisers were steaming south to draw the British ships toward the main body of the High Seas Fleet.

Naval historian John Campbell states that "Thüringen and Helgoland, and possibly Oldenburg and Posen, fired turret guns", as well as secondary weapons, at Nestor.

Oldenburg was briefly steaming unsteered, and was in danger of ramming Posen and Helgoland until Captain Höpfner managed to reach the wheel and take control of the ship.

[41][42] Despite the ferocity of the night fighting, the High Seas Fleet punched through the British destroyer forces and reached Horns Reef by 4:00 on 1 June.

[43] A few hours later, the fleet arrived in the Jade; Thüringen, Helgoland, Nassau, and Westfalen took up defensive positions in the outer roadstead and Kaiser, Kaiserin, Prinzregent Luitpold, and Kronprinz anchored just outside the entrance locks to Wilhelmshaven.

[45] The hit from Fortune was the only damage the ship incurred from enemy action,[46] though a misfire occurred in the Number 4 port-side 15 cm gun.

[50] On the approach to the English coast during the action of 19 August 1916, Scheer turned north and aborted the bombardment after receiving a false report from a zeppelin about a British unit in the area.

[52] On 25–26 September, Oldenburg and the rest of I Squadron covered an advance conducted by the II Führer der Torpedoboote (Leader of Torpedo Boats) to the Terschelling Bank.

During Operation Albion, the amphibious assault on the Russian-held islands in the Gulf of Riga, Oldenburg and her three sisters were moved to the Danish straits to block any possible British attempt to intervene.

[49] Oldenburg took the ship in tow, and the main body of the fleet turned back to Germany while Hipper searched in vain for the convoy.

German intelligence had incorrectly placed the date for the scheduled convoy on 24 April, and after several hours of fruitless steaming, Hipper turned for port as well.

Scheer—by now the Grand Admiral (Großadmiral) of the fleet—intended to inflict as much damage as possible on the British navy to improve Germany's bargaining position, despite the expected casualties.

[10] The fate of the eight remaining German battleships was determined in the Treaty of Versailles, which stated that the ships were to be disarmed and surrendered to the governments of the principal Allied powers.

The Japanese Navy had no need for the ship; she was sold to a British ship-breaking firm in June 1920 and broken up for scrap the following year in Dordrecht.