Snorkelling in Silfra Fissure

Silfra is the only place on the planet where you can swim in the gap between two continental plates. The fissure sits in Iceland's Þingvellir, on the boundary where the North American and Eurasian plates are slowly pulling apart, and it's filled with glacial meltwater filtered for decades through porous lava — leaving water so pure the visibility runs to a hundred metres. You can see further underwater here than most people can through air on a foggy day.

Floating down the flooded rift, rock walls dropping away into impossible blue clarity on either side, is a genuinely surreal half-hour. No certification is needed — it's a snorkel, not a dive — and a drysuit is supplied, which you'll be grateful for, because the water holds a constant two degrees.

It's guided-only, for good reason, and runs year-round. Come for the clarity and the geology; there's little marine life to speak of, but the water itself is the entire point.

Drysuit supplied, no diving certification required for the snorkel option, forty minutes from Reykjavík, current does the swimming.

Book a guided drysuit snorkel tour from Reykjavík — no dive certification needed. Guided operators only; minimum age and drysuit-fit requirements vary by operator, so check when booking.