Set within Thingvellir National Park, the Silfra fissure is the only place in the world where you can swim between two tectonic plates — the North American and the Eurasian. Without hyperbole, it is an utterly unique site. It’s frigid, rather regulated and requires a drysuit certification to view. At first glance, the parameters — and the rugged underwater landscape — seem to reserve this place for the steely adventurers only, but surprisingly, Silfra is genuinely accessible. We know because we did our due diligence. Read on to find all the details about the location, how to do it right and the gear that you’ll want with you for the journey.

The Setting
Translating to “Assembly Plains,” Iceland’s Althing, or parliament (the oldest surviving in the world), was established and convened in Thingvellir National Park from 930 until 1798. The park itself, a UNESCO World Heritage site, has deep historical significance beyond the incredible natural beauty found within its 22,907 acres.

The vastness of the park is interspersed with geysers and waterfalls and is anchored by Lake Thingvallavatn, Iceland’s largest at 32 square miles. Situated about 100 meters above sea level, the lake has a maximum depth of 114 meters. The surrounding land and the earth under the water is rocky basalt with the lake itself being filled by runoff from the Langjökull glacier. To reach the lake, water flows through the surrounding lava-formed rock, a process that takes anywhere between 30 and 100 years — meaning what ends up here is ultra-pure and crystal clear.

Earthquakes in 1789 are responsible for the rift between the two tectonic plates at Silfra. The continents here continue to move about 2 cm per year and earthquakes have continued to shape the underwater architecture, making this very much of a living, changing dive site.

The Dive
With temperatures remaining between 35 and 39 degrees Fahrenheit year-round, diving in Iceland may not be for the faint of heart. Beyond mental preparation for the temperature, there are a number of things you’ll have to do to gear up for a visit. Firstly, you’ll want to partner with a guide service. There are a number of regulations within the park — for example, it’s not allowed to dive below 18 meters or to enter caves. And, no matter how experienced, divers are prohibited to venture out alone. Beyond keeping it legal, the right service can provide not only the gear you need but the right expertise to maximize your experience and understanding of this unique site.

We recommend starting with Dive.is based in Reykjavik. The dive center, operating since the 1990s, offers a number of services and has very skilled instructors. At the very base, if you are Open Water certified, you can book a one or two-day drysuit course to get quickly certified to dive at Silfra. Next, they will provide all of the essential gear needed for a dive here (which even if you are an experienced diver may come in handy as not everyone wants to cart a dry suit with them during air travel). Finally, and most importantly, Dive.is offers private tours. Silfra is a spectacle and it’s one that is best enjoyed without a large group. Due to its rightful popularity, that can be a challenge. The park starts to fill around 8:30 am so a private tour in the early hours of the morning is highly recommended. It is well worth waking before dawn.

To access the site is quite easy: There is a simple, metal platform and staircase that leads divers into the water at the fissure. But what you will see below the surface is truly like nothing else. The rift itself is a relatively small area, approximately 600 by 200 meters. Silfra has four main areas to traverse — the Silfra Big Crack, Silfra Hall, Silfra Cathedral and the Silfra Lagoon. The Big Crack spans the first 120 meters in length and is also the narrowest point between the two plates. Silfra’s incredible visibility is perhaps best appreciated at the Cathedral where the walls are some 100 meters long and 20 meters deep and where it’s possible to see to its farthest end, over 100 meters.

What else can you see? Due to the young age of the volcanic rock, the lake’s water is also rich in minerals allowing for diverse life. There is rich vegetation — a total of 150 types of plants have been found within the lake — as well as 50 kinds of invertebrates. Though algae aren’t typically exciting, in the summer you’ll find that it glows an eye-popping neon green. Fish are scarce in Silfra itself but there is a second permitted dive location nearby, Davidsgja, where it’s more likely to see trout and Arctic charr.

The Gear

Bringing a proper dive watch is our first priority. For this dive, we kitted up with Panerai’s Submersible Carbotech™. This Submersible comes with improved readability: Panerai used a new technique cutting markers out of solid blocks of lume, giving the markers a 3D quality and greater visibility in deep and murky waters. Beyond this, the proprietary material produces a timepiece that’s incredibly lightweight and highly durable. It’s an ideal companion for a dive as rugged as this one — especially with gear that’s already weighing you down. Not to mention, with an accordion rubber strap, it was an easy fit over a drysuit.

There are more than a few pieces of gear that are essentials on this dive. As mentioned, most can be provided by a local dive center so we will call out only some of the highlights. To dive at Silfra, we used Bare XCS2 Tech Dry Drysuits with C-200 undergarments. The hood and gloves were both 7mm Neoprene. For BCDs and Regulators, our team was equipped with the Aqualung Pro HD and Aqualung Core. Beyond these essentials, we recommend quick-dry long underwear, extra warm socks (plus a spare set) and anything that can help raise your body temp post-dive. While the dive itself takes only about 30 minutes, it can take some time to bounce back. It’s nothing a hot drink and some extra Vitamin C can’t conquer.