The wreckage was found three years ago at the site off the UK's east coast but has only now been identified.
In September 2012, development partners SPR and Vattenfall were completing routine seabed scanning for the development of projects in the East Anglia Zone, when they came across the wreck of an uncharted submarine 90km from shore.
As an official military maritime grave, the wreck will remain in its final resting place and plans for any offshore wind development will be progressed to ensure no disturbance to the area, according to SPR.
ScottishPower Renewables is developing the 714W East Anglia One offshore project in North Sea off Suffolk, in the southern area of the zone. The cable route investigation was completed at the end of 2015, and the developer is now awaiting a final investment decisioin on the project, which will be the first wind farm to be constructed in the zone.
The submarine wreck was initially thought to be of Dutch military submarine HNLMS O13. The vessel is the Dutch Navy's last remaining lost WWII submarine, missing in action since June 1940.
The Royal Netherlands Navy was notified and divers were sent to investigate, however video footage showed the submarine was actually of German origin.
After being identified from German drawings, it was confirmed that the wreckage found was in fact that of a German World War I submarine, SM U-31, missing in action since 1915.
This submarine was the first of eleven U-31 type German submarines built between 1912 and 1915 (named U-31 to U-41).
Eight of these were sunk during the war and of these the whereabouts of two were unknown. Since the confirmation this is the lost wreckage of SM U-31, one of these mysteries has been solved.
"On 13th January 1915, the U-31 slipped its mooring and sailed north-west from Wilhelmshaven for a routine patrol and disappeared. It is thought that U-31 had struck a mine off England's east coast and sank with the loss of its entire complement of 4 officers and 31 men," said Historic England marine archeologist Mark Dunkley.
