The HMS G8 was declared missing on 14 January 1918, a week after it failed to return to its base on the River Tees on the planned date.
Gert Normann Andersen, Director of the Jutland Sea War Museum, said in a press release that he was certain that his team had found the vessel, more than a century after its disappearance.
“The wreck is draped in trawling nets, which makes it hard to see all the details, but I have no doubt that this is the G8,” he said.
The wreck was found using a 3D multibeam scanner, which identified a submarine of the same length and breadth as the G8. An underwater submarine equipped with a camera then sent back images confirming the find.
The G8 embarked from the Tees on its final patrol on 27 December 1917, accompanying the submarine HMS G12 and the destroyer HMS Medea, en route to the Kattegat.
The vessel was ordered to return on 3 January 1918, but did not arrive on 6 January as planned.
From the images, Andersen said it seemed clear that the G8 had sunk as the result of an accident or malfunction rather than falling victim to German mines or torpedoes.
“So many submarines went down with mines or torpedoes and you can easily see it, but this submarine you don't see anything, so I don't think there's been any explosions,” he told The Local.
In its press release, the museum said there were signs that the crew had been attempting to bring the vessel to the surface when it sank.
“The prow is pointing sharply upwards, which indicates that an attempt has been made to float the submarine to the surface after an accident of some kind,” the museum said.
The submarine patrolled the seas from the north of Shetland all the way through the Skagerrak sea to the Kattegat between Denmark's Jutland peninsular and Sweden, looking for German submarines.
There are no plans to salvage the vessel.