HM MGB 657 - Istria Peninsula

We love the HM MGB 657 wreck for its simplicity and historical punch. It’s sitting upright in just 12 meters, making it incredibly accessible, even for newer divers or those who just want a long, relaxed bottom time. You can trace its entire 33.5-meter length, picturing the crew on patrol back in '44 before that mine hit. The MGB 657 is now a home for moray eels tucked into the superstructure and schools of damselfish flitting around the old gun mounts. We always enjoy spotting octopus camouflaged against the hull plating; sometimes they're right out in the open, pretending to be part of the wreck itself. Because it's so shallow, light penetration is excellent, illuminating the details of the gunboat and creating a shimmering effect on the metal. It’s not about grand scale here; it's about the tangible history and the way marine life has reclaimed it. Our favourite time to dive it is early morning before the boat traffic picks up, when the visibility often feels a little crisper.

Location
Istria Peninsula, Croatia, Mediterranean & Europe
Coordinates
44.167330, 12.633166
Type
wreck
Maximum Depth
12m

Best Time to Dive in Istria Peninsula

The warmest water temperatures in Istria Peninsula occur in August, averaging 26.1°C. The coolest conditions are in March at 11.8°C.

Monthly Water Temperatures

  • January: 13.5°C
  • February: 11.9°C
  • March: 11.8°C
  • April: 13.4°C
  • May: 17.0°C
  • June: 22.4°C
  • July: 25.6°C
  • August: 26.1°C
  • September: 23.6°C
  • October: 20.3°C
  • November: 17.8°C
  • December: 15.8°C

Nearby Dive Sites in Istria Peninsula

Nearest Dive Centres to HM MGB 657

Marine Life in Istria Peninsula

Home to 48 recorded species including 28 reef fish, 7 sharks & rays, 3 other, 2 crabs & lobsters, 2 octopus & squid, 1 whales & dolphins.

Notable Species

Recommended Packing List for HM MGB 657

Based on average water temperature of 18.3°C, currents 2 cm/s.

  • Wetsuit (3-5mm) - comfortable for 18°C water
  • 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