The "U-7" class was seen by the Austro-Hungarian Navy as an improved version of its "U-3" class, which was also a Germaniawerft design. As designed for the Austro-Hungarian Navy, the boats were to displace on the surface and while submerged. The doubled-hulled boats were to be long overall with a beam of and a draft of . The Austrian specifications called for two shafts with twin diesel engines ( total) for surface running at up to , and twin electric motors ( total) for a maximum of when submerged. The boats were designed with five torpedo tubes; four located in the bow, one in the stern. The boats' armament was to also include a single L/26 deck gun.