Snorkelling between tectonic plates at Silfra in Iceland’s Thingvellir National Park

Remember those geography lessons at school where you learnt about continental drift and the movement of the earth’s crust? Iceland lies along the mid-Atlantic Ridge and exists because of the divergence of two tectonic plates – the North American plate and the Eurasian plate – and a great place to see this first hand is at Silfra in the Þingvellir National Park. What’s more, this is the only place in the world where you can snorkel between two continents.

Silfra and the Þingvellir valley, situated within Iceland’s Golden Circle, were formed by the divergent tectonic drift of the the two plates which drift about 2 cm farther apart every year. This builds tension between the plates and the earth mass above which is relieved through periodic major earthquakes that occur at approximately ten year intervals. These earthquakes create cracks and fissures and Silfra, which lies at the rim of the Þingvallavatn Lake, is one of the largest and deepest of these fissures.

This fissure is fed by meltwater from Iceland’s second largest glacier, Langjökull, which seeps underground into porous basalta lava rock before percolating through an aquifer over a period of 30-100 years. This highly filtered groundwater fills fissures such as the one at Silfra, making it exceptionally clear and of huge appeal snorkelers and scuba divers, particularly given the unique location between two tectonic plates.

There are a number of companies that offer snorkeling and diving experiences.  We went with DIVE.is who are one of the experts for this particular activity and the longest running dive and snorkel company in Iceland. The process was quite straight forward – we just turned up at the Silfra meeting point, had our booking and disclaimers checked in the back of a van (it is mandatory for every DIVE.is participant to fill out their medical form), and we were good to go. With certain medical conditions such as heart disease, epilepsy or lung disease, it is unfortunately not possible to take part. With certain other medical conditions such as asthma, high blood pressure, vertigo or cancer, you can only participate if you get medical clearance from a doctor.

We were then assigned a guide who would accompany us on the snorkeling tour – in our case, a…