In addition to being used by Seebataillon units the 6 cm S-Bts K L/21 was used by the Schutztruppe in Germany's colonial empire. They may have been used before World War I during the Boxer Rebellion, the Herero Wars or the Maji Maji Rebellion. In the African theater of World War I, the SMS Königsberg sent its guns ashore to serve with the Schutztruppe in German East Africa in August 1914. Another two guns arrived in East Africa on board the blockade runner, SS Rubens in 1916. Beginning in 1915, several naval infantry units armed with 6 cm S-Bts K L/21 guns were based in the Flanders region of Belgium. They are believed to have been used as infantry support guns due to their ability to be easily transported over soft ground.