Stuttgart was used as a gunnery training ship from her commissioning to the outbreak of World War I in August 1914, when she was mobilized into the reconnaissance forces of the High Seas Fleet.

This was a result of budgetary constraints that prevented the Kaiserliche Marine (Imperial Navy) from building more specialized cruisers suitable for both roles.

All four members of the class were intended to be identical, but after the initial vessel was begun, the design staff incorporated lessons from the Russo-Japanese War.

The ship's propulsion system was rated to produce 13,200 metric horsepower (9,700 kW) for a top speed of 23 knots (43 km/h; 26 mph), though she exceeded these figures in service.

From 1 April to 1 June 1910, she cruised in the North Sea in company with the armored cruiser Prinz Adalbert and visited the Faroe Islands; during the voyage, the ships conducted shooting practice.

She was present for a naval review held in Danzig Bay on 28 August for Kaiser Wilhelm II, and she again participated in the autumn fleet exercises that followed immediately thereafter.

[6] A particularly cold winter in February 1912 led to Stuttgart being employed as an ice breaker to assist merchant vessels in the Baltic.

[6] At the outbreak of World War I in late July 1914, Stuttgart was in the shipyard in Danzig; she left the harbor on 6 August and arrived in Wilhelmshaven the following day.

On 25–26 August, Stuttgart led a mine-laying operation in the North Sea, escorting the mine-layin cruiser Albatross along with several torpedo boats.

Stuttgart briefly moved to the Baltic from 8 to 17 November, after which she resumed her role in the fleet's cruiser screen for the next operation against the British coast.

This took place on 15–16 December, which again saw the battlecruisers of Rear Admiral Franz von Hipper's I Scouting Group bombarded Scarborough, Hartlepool, and Whitby.

[6][7] Following reports of British destroyers from the German screen, Admiral von Ingenohl ordered the High Seas Fleet to turn to port and head for Germany.

At 08:02, however, Roon signaled the two light cruisers and ordered them to abandon the pursuit and retreat along with the rest of the High Seas Fleet.

[6] On 7 May 1915, IV Scouting Group, which by then consisted of Stuttgart, Stettin, the light cruisers München, and Danzig, and twenty-one torpedo boats was sent into the Baltic Sea to support a major operation against Russian positions at Libau.

IV Scouting Group was tasked with screening to the north to prevent any Russian naval forces from moving out of the Gulf of Finland undetected, while several armored cruisers and other warships bombarded the port.

Shortly after the bombardment, Libau was captured by the advancing German army, and Stuttgart and the rest of IV Scouting Group were recalled to the High Seas Fleet by 9 May.

IV Scouting Group—which now consisted of Stuttgart, Stettin, and the light cruisers Berlin and Kolberg—carried out a patrol into the Hoofden on 1–2 July, but again, no British ships were seen.

On 25 March, the fleet went to sea again in an unsuccessful attempt to destroy British seaplane carriers that had raided the German airbase at Tondern.

IV Scouting Group, under the command of Commodore Ludwig von Reuter, departed Wilhelmshaven at 03:30 on 31 May, along with the rest of the fleet.

Stuttgart and IV Scouting Group were not heavily engaged during the early phases of the battle, but around 21:30, they encountered the British 3rd Light Cruiser Squadron (3rd LCS).

[12] During the ferocious night fighting that occurred as the High Seas Fleet forced its way through the British rear, IV Scouting Group encountered the 2nd Light Cruiser Squadron at close range in the darkness.

In the melee, the cruiser Frauenlob was hit and sunk by a torpedo launched by Southampton; this forced Stuttgart to haul out of line to starboard.

[17] Stuttgart next went to sea with the rest of the fleet on 19–20 August, which resulted in the abortive action of 19 August 1916,[11] which saw the British and German fleets initially attempt to engage each other, but both sides disengaged, the British after losing a cruiser to a U-boat and the Germans after failing to locate the detached Harwich Force.

[19] On 1 December, the units of the High Seas Fleet were reorganized, and many of the older ships, which were inadequately protected against torpedo or mine damage, were withdrawn so their crews could be used elsewhere.

[11] By this time, it had become increasingly clear that the High Seas Fleet needed seaplane carriers that could accompany it to provide fast aerial reconnaissance.

Eventually, on 20 January 1918, the naval command was finally able to convince the RMA that Stuttgart and Stettin should be converted into fast seaplane tenders.

The order to convert the vessels was issued on 24 January, but the question of the nature of the conversion had not yet been settled: should they be lightly armed seaplane tenders or should they retain some of their original armament as aircraft cruisers?

The ship carried out initial training in the Baltic, and by late July, she began operations in the German Bight to cover the minesweepers clearing paths in the minefields there.

[22] Since Stuttgart could carry only three aircraft, a number which was deemed insufficient to support the entire High Seas Fleet, plans were drawn up to convert Roon into a seaplane carrier as well, but the Kaiserliche Werft in Wilhelmshaven informed the naval command that work could not begin until early 1919.