In two patrols UC-43 was credited with sinking 13 ships, either by torpedo or by mines laid.

The submarine was powered by two six-cylinder four-stroke diesel engines each producing 260 metric horsepower (190 kW; 260 shp) (a total of 520 metric horsepower (380 kW; 510 shp)), two electric motors producing 460 metric horsepower (340 kW; 450 shp), and two propeller shafts.

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 60 nautical miles (110 km; 69 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 9,410 nautical miles (17,430 km; 10,830 mi) at 7 knots (13 km/h; 8.1 mph).

UC-43 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.