He was present on U-20, but left prior to the U-20's sinking of RMS Lusitania in 1915. He exclusively commanded small, coastal U-boats, starting with UB-2 in February 1915. He went on to command six subsequent UB and UC-type boats, during which time he was awarded the Iron Cross, Second and First class. His last command was UB-110, which was depth-charged and rammed by HMS Garry on July 19, 1918. Twenty-one of the 34 crew were killed, and Fürbringer was captured. He spent the rest of the war as a British prisoner of war.