Riff Williams - Istria Peninsula

The HMS *Sphinx*, a Halcyon-class minesweeper, sits upright in Scapa Flow, a haunting reminder of her wartime service. We love diving this wreck because it’s a proper expedition, a tangible link to history that you can actually touch. Dropping down, you’ll find her surprisingly intact, still holding her shape with deck guns visible and parts of the superstructure standing proud. We’ve spent hours here, poking into the open hatches, imagining the lives of the crew. The marine life here is classic Scapa Flow; less about colourful corals and more about the hardy residents that thrive in colder waters. Look for curious common seals often making fly-bys, their eyes watching you from the gloom. Our favourite moments are when the light penetrates just right, illuminating the shoals of small fish darting through the rusted metalwork. It’s a dive for those who appreciate history as much as the underwater world, and while it’s not a super deep dive, the currents can be tricky, so we’d suggest it’s best for experienced cold-water wreck divers. Dive her at slack water if you can; it makes all the difference to really take in the scale of her.

Location
Istria Peninsula, Croatia, Mediterranean & Europe
Coordinates
47.284847, 8.608411
Type
wreck

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 Riff Williams

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 Riff Williams

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