SMS Thetis was the fourth member of the ten-ship Gazelle class of light cruisers that were built for the German Kaiserliche Marine (Imperial Navy) in the late 1890s and early 1900s.

Built to be able to serve with the main German fleet and as a colonial cruiser, she was armed with a battery of ten 10.5 cm (4.1 in) guns and a top speed of 21.5 knots (39.8 km/h; 24.7 mph).

This period passed uneventfully, though she served as the flagship of light forces in the Baltic and she made several visits to foreign ports in the region.

Thetis carried 560 t (550 long tons) of coal, which gave her a range of 3,560 nautical miles (6,590 km; 4,100 mi) at 10 knots (19 km/h; 12 mph).

[5] Thetis was ordered under the contract name "C" and was laid down at the Kaiserliche Werft (Imperial Dockyard) in Danzig in September 1899 and was launched on 3 July 1900.

The commander of the squadron, Vizeadmiral (Vice Admiral) Richard Geissler, came aboard the ship for a cruise in the Yangtze river on 28 April.

After the outbreak of the Russo-Japanese War in February 1904, Thetis was sent to Chemulpo in the Korean Empire to evacuate German nationals from the country.

She left Hong Kong on 28 August and arrived in East Africa on 26 September; the unprotected cruiser Seeadler joined her there on 1 October.

Since Glatzel was the senior-most captain of the vessels in the area, which also included the unprotected cruiser Bussard, the station ship in East Africa, he became the commander of the naval forces in the region.

[6] Following the start of World War I in July 1914, Thetis was recommissioned on 4 August and assigned to the Coastal Defense Division of the Baltic Sea, commanded by KAdm Robert Mischke.

Work to ready the ship for wartime service was completed by 24 August, and she was thereafter deployed to patrol the Danish straits to guard against incursions by British warships.

Thetis was transferred on 18 October to the Detached Division, commanded by KAdm Ehler Behring; the unit was tasked with offensive operations against Russian forces in the eastern Baltic.

While on the way back on the night of 6 November, Thetis's crew observed a pair of ships in the distance, but her commander, FK Paul Nippe, failed to report the sighting.

As it turned out, the vessels Thetis had observed were four Russian destroyers that had laid a minefield off Memel that claimed Behler's flagship, the armored cruiser Friedrich Carl, on 17 November.

[7] Behring led another sweep into the direction of Åland that lasted from 15 to 18 December; Thetis and the light cruiser Lübeck screened the eastward flank by patrolling off Utö, protecting the main German element from being surprised by Russian vessels that might sortie from the Gulf of Finland.

Thetis and several other cruisers and torpedo boats covered the assault on the city and patrolled to ensure no Russian naval forces attempted to intervene.

On 3 June, Thetis, four torpedo boats, and a seaplane tender attempted to force the Irben Strait, where they intended to lay a minefield.

The Russian submarine Okun attempted to move into position to attack Thetis, but one of the torpedo boats spotted her periscope and forced it off.

On 5 June, the British submarine HMS E9 arrived on the scene, by which time the German vessels had withdrawn to the western coast of Gotland.

On 19 July, Thetis was based in Windau for a planned attack on the Gulf of Riga by elements of the High Seas Fleet.

[11] In August, Thetis was assigned to the fleet that was to break into the Gulf of Riga to support the German Army's attempt to capture the city.

On 8 August, the Germans made their first attempt to force the Irben Strait, during which Thetis and the torpedo boat S144 were damaged by mines.

At the same time, the fleet was reorganized and Thetis became the flagship of light naval forces in the Baltic, which also included her sister ship Medusa and I Torpedo-boat Flotilla.

[14] Thetis made another pair of foreign visits in July 1924, both to ports in Estonia, one of the countries that had been created from the dissolution of the Russian Empire after the war.

The vessel was thereafter used as a barracks ship in Wilhelmshaven until early 1929; struck from the naval register on 27 March, she and the torpedo boats V1 and V6 were sold to Blohm & Voss.