SM UB-107 was a German Type UB III submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. She was commissioned into the German Imperial Navy on 16 February 1918 as SM UB-107.

The submarine conducted 4 patrols and sank 11 ships during the war for a total loss of 26,147 GRT. UB-107 was sunk on 27 July 1918 by HMS Vanessa (D29) and HMT Calvis at 54°23′N 0°24′W / 54.383°N 0.400°W / 54.383; -0.400.

UB-107 was ordered by the GIN on 23 September 1916. She was built by Blohm & Voss of Hamburg and following just under a year of construction, launched at Hamburg on 21 July 1917. UB-107 was commissioned early the next year . Like all Type UB III submarines, UB-107 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun. UB-107 would carry a crew of up to 3 officer and 31 men and had a cruising range of 7,420 nautical miles (13,740 km; 8,540 mi). UB-107 had a displacement of 519 t (511 long tons) while surfaced and 649 t (639 long tons) when submerged. Her engines enabled her to travel at 13.3 knots (24.6 km/h; 15.3 mph) when surfaced and 7.4 knots (13.7 km/h; 8.5 mph) when submerged.

The first recorded fate of UB-107 was noted as sunk by depth charge on 27 July 1918 by the Royal Navy trawler Calvia and destroyer Vanessa at position 54°23′N 00°24′E / 54.383°N 0.400°E / 54.383; 0.400. It has since been argued that the UB-107 was probably not present for the attack by Calvis and Vanessa as it was the only U-boat that could have been responsible for the sinking of steamers Chloris and John Rettig two and a half hours later at position 53°52′N 00°10′E / 53.867°N 0.167°E / 53.867; 0.167.

In 1985 divers discovered the wreck of UB-107 one mile north of Flamborough Head at position 54°08′N 00°00′W / 54.133°N -0.000°E / 54.133; -0.000 entangled with another wreck, the SS Malvina, a British steamer torpedoed and sunk on 3 August 1918 reported as being by UB-104, though UB-104's record says it was not in the area nor that it attacked a ship on that day. UB-107 was identified by the markings on her propellers. It is suggested that either UB-107 suffered an accident of some sort or was lost on a British mine between 28 July and 3 August 1918, leaving all hands lost (38 dead).

Date	Name	Nationality	Tonnage	Fate
10 May 1918	Erich Lea	Norway	1,630	Sunk
10 May 1918	Naparima	Sweden	1,685	Damaged
6 June 1918	Koningin Regentes	Netherlands	1,970	Sunk
8 June 1918	Hogarth	United Kingdom	1,231	Sunk
13 June 1918	Agnes	Sweden	1,334	Sunk
13 June 1918	Kalo	United Kingdom	1,957	Sunk
15 June 1918	Kieldrecht	United Kingdom	1,284	Sunk
8 July 1918	Chicago	United Kingdom	7,709	Sunk
8 July 1918	War Crocus	United Kingdom	5,296	Sunk
9 July 1918	Fryken	Sweden	943	Sunk
27 July 1918	Chloris	United Kingdom	984	Sunk
27 July 1918	John Rettig	Sweden	1,809	Sunk

The fate of UB-107 was the subject of an episode of the documentary television series Deep Sea Detectives: "Mystery U-Boat of WWI". The documentary offered various scenarios for the sinking based on historical evidence and exploratory diving at the wreck site.

• MaritimeQuest Daily Event SMS UB-107