NBM Dive Site Resource
SM U-31
Caister-on-Sea offshore, Norfolk / southern North Sea, United Kingdom
An early ocean-going submarine identified during offshore wind-farm investigations. Identified through documented Navy and specialist diver visits. Remote offshore military grave; check current wind-farm, marine and heritage access requirements.
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Featured Hero Photograph
Aquatic life at this dive site
What divers may encounter
Three reviewed connections are featured here. Sightings vary by season, conditions, and chance, so they are never guaranteed.
Aquatic life research in progress
NBM is reviewing a likely local species for this position.
Aquatic life research in progress
NBM is reviewing a likely local species for this position.
Aquatic life research in progress
NBM is reviewing a likely local species for this position.
Site media
Photographs
Three views rotate from the published gallery on each visit.
Contributor media
Dive videos
Three featured video positions are reserved on every profile.Regional location and nearby land
Location map
Regional overview includes nearby land for orientation. It does not establish a navigation waypoint or an entry location.Map data © OpenStreetMap contributors
Recent field observations
Diver-reported temperatures
Automatically checked observations from dives during the past 14 days. Three reports are visible at a time; scroll for more.A report that passes the automatic checks will appear here with the dive date, diver’s display name, and temperatures at each depth.
Reports are automatically checked for plausible dates, depths, and temperatures. They are observations, not forecasts; confirm conditions before diving.
Why divers know this place
Highlights
Early ocean-going submarine with surviving tower and partly buried bow.
Shipwreck-only module
The wreck
This section appears only on shipwreck records and brings the vessel, its loss, present condition, access, and responsible wreck-diving considerations into one place.
- Vessel type
- German Type U 31 submarine
- Year built
- 1914 (launched)
- Year sunk
- 1915
- Cause of loss
- Lost after departing on patrol in January 1915, probably to a mine.
- Present condition
- Early ocean-going submarine with surviving tower and partly buried bow.
- Penetration guidance
- External wreck context only. This record does not authorize penetration or artifact recovery.
Before you arrive
Access notes
Identified through documented Navy and specialist diver visits. Remote offshore military grave; check current wind-farm, marine and heritage access requirements. Confirm current access, restrictions, weather, tidal windows and support before planning a visit.
Plan within your training
Conditions and hazards
Depth, decompression exposure, currents, sea conditions, fishing gear, damaged metal and fragile wreck structure. Respect any human remains and do not disturb objects.
Independent resource notice
This record is a starting point for independent verification. Access, closures, moorings, weather, currents, depth, visibility, operator availability, and site conditions can change without notice. Confirm current information with the responsible operator, property owner, managing authority, or another qualified local source before planning or attempting a dive.