HM submarine A3 - Cornwall & Devon

The HM submarine A3 is a real treat for anyone who loves a bit of history with their diving. This isn't some broken-up pile of metal; she sits upright and largely intact at 32 metres, a proper time capsule. Dropping down, you'll see her shape emerge from the gloom, long and slender, almost exactly as she looked when she sank in 1912 after a collision. We particularly love the feeling of swimming along her deck, imagining the crew on board. While the conning tower hatch is gone, and a few windows are open, the pressure hull is remarkably preserved. You can’t penetrate, of course, but just seeing the torpedo tubes still in place, peering into those open spaces, gives you a shiver. It’s dark down there, even on a sunny day, so good lights are essential to pick out the details and the marine life that has made her home. Expect to find plenty of crabs tucked into crevices, some respectable lobsters under the hull, and often a decent sized conger eel or two peeking out. It’s a site that really makes you think, a sombre reminder of naval history, and our pick for anyone who appreciates the quiet dignity of a well-preserved wreck.

Location
Cornwall & Devon, United Kingdom, Mediterranean & Europe
Coordinates
50.523720, -2.188579
Type
wreck
Maximum Depth
32m

Marine Protected Area: Studland to Portland

Best Time to Dive in Cornwall & Devon

The warmest water temperatures in Cornwall & Devon occur in January, averaging 9.6°C. The coolest conditions are in December at 9.6°C.

Monthly Water Temperatures

  • January: 9.6°C (air: 7.3°C)
  • February: 9.6°C (air: 8.4°C)
  • March: 9.6°C (air: 8.6°C)
  • April: 9.6°C (air: 10.1°C)
  • May: 9.6°C (air: 12.6°C)
  • June: 9.6°C (air: 15.2°C)
  • July: 9.6°C (air: 16.6°C)
  • August: 9.6°C (air: 17.1°C)
  • September: 9.6°C (air: 15.9°C)
  • October: 9.6°C (air: 13.5°C)
  • November: 9.6°C (air: 10.7°C)
  • December: 9.6°C (air: 8.7°C)

Nearby Dive Sites in Cornwall & Devon

Nearest Dive Centres to HM submarine A3

Marine Life in Cornwall & Devon

Home to 192 recorded species including 93 reef fish, 18 sharks & rays, 13 whales & dolphins, 11 crabs & lobsters, 11 other, 10 seagrass & algae.

Notable Species

Recommended Packing List for HM submarine A3

Based on average water temperature of 9.6°C.

  • Drysuit - water at 10°C demands a drysuit with thermal undergarments
  • Hood & Gloves (7mm+) - critical to prevent heat loss
  • Mask - essential for every dive
  • Fins
  • BCD - buoyancy compensator
  • Regulator - your most safety-critical piece of gear
  • Dive Computer - tracks depth, time, and NDL
  • Surface Marker Buoy (SMB) - essential for boat pickups
  • Dive Torch - useful for crevices and colour at depth
  • Underwater Camera - capture your diving memories