[Note 1] In seven patrols UC-33 was credited with sinking 36 ships, either by torpedo or by mines laid.

UC-33 was shelled and then rammed by patrol boat PC61 captained by Frank Worsley at position 51°55′N 6°14′W / 51.917°N 6.233°W / 51.917; -6.233 in St. George's Channel on 26 September 1917.

She had a dive time of 48 seconds and was capable of operating at a depth of 50 metres (160 ft).

When submerged, she could operate for 53 nautical miles (98 km; 61 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 10,040 nautical miles (18,590 km; 11,550 mi) at 7 knots (13 km/h; 8.1 mph).

UC-33 was fitted with six 100 centimetres (39 in) mine tubes, eighteen UC 200 mines, three 50 centimetres (20 in) torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one 8.8 cm (3.5 in) Uk L/30 deck gun.