SM UB-28 was a German Type UB II submarine or U-boat in the German Imperial Navy () during World War I. The U-boat was ordered on 30 April 1915 and launched on 20 December 1915. She was commissioned into the German Imperial Navy on 27 December 1915 as SM UB-28. UB-28 was surrendered to Britain in accordance with the requirements of the Armistice with Germany on 24 November 1918. She was ultimately broken up at Bo'ness in 1919-20.