On 18 November 1917 the U-boat sailed for Pola, where she was commissioned as SM U-22 on 23 November under the command of Linienschiffsleutnant Josef Holub.[5] The 31-year-old Galician had been assigned to U-22 in February and had been in charge of sister boat U-21 from June 1916 until his assignment to U-22.[9]