Pumpwerk Horgen - Istria Peninsula
Tunnel Rock isn't about big pelagics or endless reef walls. This is for divers who appreciate the subtle, the unusual, and the thrill of exploration. We love the dramatic swim-throughs and the way the light plays as you navigate the different sections. It’s an intimate dive, a real adventure into Eleuthera’s unique geology. Drop down and you're immediately drawn into a labyrinth of rock formations. Our favourite part is the main tunnel itself, a wide, dark cavern that feels like something out of a Jules Verne novel. Keep an eye out for viperfish lurking in the shadowy corners, and we’ve spotted roughhead blennies peeking from crevices more than once. The ambient light shifts from bright Caribbean blue to a muted grey as you penetrate deeper, then bursts back as you emerge into an open-air chamber. It's a fantastic spot for underwater photographers looking for dramatic lighting and interesting textures. Don't expect screaming currents here, just a gentle drift, making it perfect for focused exploration.
- Location
- Istria Peninsula, Croatia, Mediterranean & Europe
- Coordinates
- 47.257030, 8.610140
- Type
- cave
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
- 100 Steps
- 1. Niederbayerischer Tauchsportclub Plattling e.V.
- 3 Zinnen - 18m
- A CAPELLINI - 11m (wreck)
- Accademia Blu Diving Center
- Allgäuer Taucherhof
- Allmannshausen: Naturschutzgebiet
- Allmannshausen: Seeburg
- Allmannshausen: Wasserwacht
- Allmannshauser Steilwand
- Almsee (reef)
- Alpenblick
- Alte Badanstalt
- Alte Brücke-Flurlingersteg
- Alte Julierbrücke
Nearest Dive Centres to Pumpwerk Horgen
- 100 x 100 Diving - PADI, TECREC, DAN, EFR
- ACQUASUB VICENZA TEAM asd
- Albarella Diving Center SSDRL
- Apnea Slovenija
- Aquaemotion SSD SRL
- Aquanautic Elba - SSI
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
- Corb (Sciaena umbra) - Reef Fish
- Cape Shark (Squalus acanthias) - Sharks & Rays
- conger (Conger conger) - Reef Fish
- Common lobster (Homarus gammarus) - Crabs & Lobsters
- Common Eagle Ray (Myliobatis aquila) - Sharks & Rays
- poor cod (Trisopterus minutus) - Reef Fish
- Blue Stingray (Pteroplatytrygon violacea) - Sharks & Rays
- Common smoothhound (Mustelus mustelus) - Sharks & Rays
- Painted Comber (Serranus scriba) - Reef Fish
- Wrasse (Coris julis) - Reef Fish
- Blackspotted Smoothhound (Mustelus punctulatus) - Sharks & Rays
- Damsel fish (Chromis chromis) - Reef Fish
- Leidy's Comb Jelly (Mnemiopsis leidyi)
- loggerhead turtle (Caretta caretta)
- Cowfish (Tursiops truncatus) - Whales & Dolphins
- Slender Seagrass (Cymodocea nodosa) - Seagrass & Algae
- hake (Merluccius merluccius) - Reef Fish
- Mullet (Mullus barbatus) - Reef Fish
- european squid (Loligo vulgaris) - Octopus & Squid
- common cuttlefish (Sepia officinalis) - Octopus & Squid
Recommended Packing List for Pumpwerk Horgen
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