While in the flotilla, UB-2 sank eleven British ships of 1,374 gross register tons (GRT) under the command of Kptlt.

At the end of the war, UB-2 was deemed unseaworthy and unable to surrender at Harwich with the rest of Germany's U-boat fleet.

[8][Note 2] UB-2 was part of the initial allotment of eight submarines—numbered UB-1 to UB-8—ordered on 15 October from Germaniawerft of Kiel, just shy of two months after planning for the class began.

During this campaign, enemy vessels in the German-defined war zone (German: Kriegsgebiet), which encompassed all waters around the United Kingdom (including the English Channel), were to be sunk.

[12] The UB I boats of the Flanders Flotilla were initially limited to patrols in the Hoofden, the southern portion of the North Sea between the United Kingdom and the Netherlands.

[14][15] All six of the smacks—sailing vessels traditionally rigged with red ochre sails[16]—were stopped, boarded by crewmen from UB-2, and sunk with explosives.

Even though none of the boats sank any ships, by successfully completing their voyages they helped further prove the feasibility of defeating the British countermeasures in the Straits of Dover.

[22] Three days later, UB-2 sank 47 GRT smack Boy Ernie about 58 nautical miles (107 km; 67 mi) east of Cromer.

Holtzendorff's directive from ordered all U-boats out of the English Channel and the South-Western Approaches and required that all submarine activity in the North Sea be conducted strictly along prize regulations.

[14] The German Imperial Navy began its second submarine offensive in February 1916, declaring, among other provisions, that all enemy vessels in the war zone were to be destroyed without warning.

[28] By early February, the Flanders Flotilla was beginning to receive the newer, larger Type UB II boats.

[29] UB-2 was transferred into the Baltic Flotilla (German: U-boote der Ostseetreitträfte V. U-Halbflotille) about a week after Neumann took command.

[1] According to authors R.H. Gibson and Maurice Prendergast, submarines assigned to training duties were "war-worn craft" unfit for service.