UC-2 sailed from Zeebrugge on 29 June 1915 to lay mines off Lowestoft. On 2 July she was accidentally run down by the coaster Cottingham off that same port; the impact tore a opening in the forward part of the pressure hull, and the submarine sank. The Cottingham's master reported the incident and the area was subsequently dragged by Royal Navy vessels, whose lines fouled an underwater obstruction and caused a substantial submerged explosion. On 3 July a diver discovered UC-2 in ; as well as the damage which had resulted from the impact with the Cottingham, he reported that one of the submarine's mines had been detonated by the drag lines.