Intermediate Greece
Santorini
Diving inside a volcanic caldera, along black walls with almost no life
About three thousand six hundred years ago, an eruption destroyed the center of this island and the sea filled the gap. What you dive today is literally the inside of a volcano: black lava walls plunging straight down for hundreds of meters, with very little life on them. And that's exactly the appeal.
In this guide you'll find out what the caldera is and how it's dived, why marine life is scarce and why that isn't a flaw, what wreck and what fumaroles are here, when to go, and what level a site with walls that have no visible bottom demands.
It's a destination of pure geology, the most extreme of its kind in Europe, and the best reminder that a dive site can be memorable without a single interesting fish.
Geography and access
Santorini is what remains of a volcano whose center collapsed after a massive eruption in the Bronze Age. Today's island is crescent-shaped and encircles a caldera flooded by the sea.
Inside that caldera the seabed drops extraordinarily fast: in the central zone it exceeds three hundred meters just a short distance from shore. Diving there means diving along a wall with no visible bottom.
The walls are dark volcanic rock, with lava flows, layers of compacted ash, and fallen boulders. The dark substrate absorbs light and gives the dives a somber character unlike anything else in the Aegean.
In the center of the caldera there are more recent volcanic islets, still active, with fumaroles that release gas and heat the water in specific shallow areas.
Access is by direct flight from Europe in season, or by ferry from the mainland and other islands. Dive outings are short, within the caldera itself.
Keep reading with full access
This article is part of the full Encyclopedia. A donation from USD 10 unlocks every article, every species photo and the downloadable app, and helps sustain the Scuba Sign Paperless Diving Community project.