Silfra is a fissure filled with fresh spring water within Þingvellir National Park, and one of the country’s most cherished wonders. Snorkelling and diving in its crystal-clear waters is an experience that is both thrilling and relaxing, and it is now considered to be one of the top five dive sites in the world. It takes around an hour to reach Silfra from Reykjavík.
Silfra fissure opened in 1789, due to the movements of the tectonic plates that frame Þingvellir National Park. The North American and Eurasian plates, which run all the way through Iceland, separate at about 2 centimetres per year, and as they do, they tear open fissures in the land between them.
Some of the ravines fill with water travelling underground through the porous lava fields in the area, originating from Langjökull glacier about 60 kilometres north. It can take the water up to a century to reach Silfra and this long filtration process results in the water being both extremely clear and drinkable.
Because the water travels underground, it maintains a constant temperature of two to three degrees Celsius and does not freeze over immediately at the source of the spring. Snorkelling and diving tours are thus open throughout the year.
The clarity of the water is what draws most visitors. The visibility can extend to over 100 metres, allowing you to see the canyon walls and bottom like you are floating over a great cathedral.
The last colour that water absorbs is blue, which means that when you look forward in Silfra, it is as if you are looking into an ethereal, vivid, azure world. The clarity also means that sun-rays refract through the surface of the water, creating rainbows on Silfra’s bed when the weather allows.
Snorkelling in Silfra fissure is a highly enjoyable activity, but you must meet some prerequisites to be able to join. These are as follows:
The most common option for snorkelling is to conduct it in a drysuit. Drysuits work with a fluffy undersuit to keep your body free from water and insulated against the cold, making the task of swimming through the near-freezing temperature more than achievable.
While drysuit snorkelling is the most comfortable and popular option, a few tours allow you to go through Silfra wearing a wetsuit. Wetsuits, made of neoprene, allow water to surround your body in a thin layer, that your body then heats up and uses to protect you. Though they grant you more flexibility, they are not so warm, so this should be done by the daring; you will also need to be at least 50 kilograms to snorkel in a wetsuit.
In all tours, you wear neoprene on your head and hands to allow for better mobility, a mask and snorkel, and a pair of fins, all of which are provided on site. The course of Silfra takes approximately forty minutes, and there is a gentle current throughout, meaning it requires minimal energy to traverse.
Diving through Silfra gives an extra dimension to its beauty, as you will be able to look up and see the sun glistening upon the surface as you cruise through the crystal clear waters. However, considering the risks associated with diving in cold water and cumbersome equipment, all who partake must meet all the requirements above, as well as one of the following: