|Port of registry||Hamburg|
|Route||Hamburg America Line's North Atlantic route|
|Fate||Destroyed April 13, 1945|
|Installed power||2 x 3 cyl. triple expansion engines, dual shaft|
The ship was built in 1905 at the Schichau Seebeck shipyard in Bremerhaven for the Hamburg-American Packetfahrt-Actien-Gesellschaft (HAPAG or Hamburg America Line). In 1918 Thomas Kier, formerly captain of the SS Imperator, became captain of the Karlsruhe. In 1935 the ship was acquired by the Ernst Russ Reederei and it stayed in service for them until 1945.
On April 11, 1945, the Karlsruhe took 1,083 refugees on board in Pillau (today Baltiysk) and left the port at around 8 p.m. for the Hel Peninsula, where the ship arrived on April 12, 1945 in the morning. There, a convoy was formed with the steamers SS Santander, SS Karlsruhe and three minesweepers, which departed at around 9 a.m for Copenhagen.
The overloaded Karlsruhe was not able to keep up with the required speed of the convoy of 9 knots, and could only run a good 7 knots, and fell behind. On April 13, 1945, she was attacked by Soviet planes north of Stolpmünde (today Ustka in Poland) and hit with a torpedo. The ship broke in two and sank in 3–4 minutes time. The minesweepers of the 25th minesweeping flotilla, M 294 (Kapitänleutnant Volberts) and M 341 (Oberleutnant zur See Henry Peter Rickmers) were able to save only 150 of the approximately 1083 refugees (M294: 63 - M341: 87). The other 933 passengers perished.
The well-preserved wreck was located and inspected by Polish divers in July 2020. There has been speculation that a number of sealed crates on board may contain parts of the Amber Room from the Catherine Palace, which was looted by the Germans in 1941 and disappeared from Königsberg in 1945.