She was built by Friedrich Krupp Germaniawerft of Kiel and following just under a year of construction, launched at Kiel on 31 May 1917. UB-66 was commissioned later that same year under the command of Kptlt. Fritz Wernicke. Like all Type UB III submarines, UB-66 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun. UB-66 would carry a crew of up to 3 officer and 31 men and had a cruising range of 9,090 nautical miles (16,830 km; 10,460 mi). UB-66 had a displacement of 513 t (505 long tons) while surfaced and 647 t (637 long tons) when submerged. Her engines enabled her to travel at 13.2 knots (24.4 km/h; 15.2 mph) when surfaced and 7.6 knots (14.1 km/h; 8.7 mph) when submerged.
^Helgason, Guðmundur. "WWI U-boat commanders: Fritz Wernicke". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 8 March 2015.
^Helgason, Guðmundur. "Ships hit by UB 66". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 8 March 2015.