She was built by Blohm & Voss of Hamburg and following just under a year of construction, launched at Hamburg on 21 July 1917. UB-108 was commissioned early the next year under the command of Oblt.z.S.Wilhelm Amberger. Like all Type UB IIIsubmarines, UB-108 carried 10 torpedoes and was armed with a deck gun. UB-108 would carry a crew of up to 3 officer and 31 men and had a cruising range of. UB-108 had a displacement of while surfaced and when submerged. Her engines enabled her to travel at when surfaced and when submerged.