Silfra · Iceland · Freshwater · Wall
Silfra Cathedral
See the full 100 m length of the corridor from its entrance
Photo: Jens Bludau · CC BY-SA 3.0
The Cathedral is the section Silfra is known for: about 100 metres long, some 20 metres deep at its deepest point, with lava walls that fall straight down on either side and top out within 30 centimetres of the surface. From the entrance you can see all the way to the far end, which is what visibility of over 100 metres actually looks like.
Also known as The Cathedral.
Where it is and how deep
64.2543° N, 21.1180° WApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
The Cathedral opens up after the 200 metre swim on from Silfra Hall. It is about 100 metres from beginning to end and roughly 20 metres deep at its deepest point, and the walls are the reason for the name: lava rock falling straight down on both sides, running from the floor to within 30 centimetres of the surface. Gazing through the section with those walls dropping away is, in silfra.org's words, one of the most dramatic views underwater.
Clarity is the other reason people come. On entering the Cathedral it is possible to see all the way to the end, which proves the visibility of over 100 metres that silfra.org calls the longest recorded anywhere in the world. The 18 metre limit on dive depth keeps you high in the section, looking down the length of it rather than along the floor.
At the far end a sand slope rises to a depth of 2 to 3 metres, and this is where the flow makes itself felt. The up-welling current here tries to push divers and snorkellers straight out into the lake, so the left-hand turn into Silfra Lagoon has to be made in good time. Take it and the dive finishes in shallow, calm water; miss it and the current carries you out of the fissure entirely.
Marine life and season
The sources we used don't single out particular species here.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fair | Fair | Good | Good | Prime | Prime | Prime | Prime | Prime | Good | Fair | Fair |
Season follows Silfra: Water temperature and clarity stay constant year-round since Silfra is fed by filtered glacial groundwater; ratings track daylight hours and road access to Þingvellir, not underwater conditions.
Know before you go
- The end of the Cathedral is the most dangerous spot in Silfra: up-welling current over the 2-3 m sand slope pushes divers toward the open lake unless the left turn into the Lagoon is made in time.
Dive videos
Diving at Silfra, Iceland · gramsmose on YouTube
Tauchen in Silfra, Island - Diving Silfra, Iceland · StefanSchneider22 on YouTube
Questions divers ask
How deep is Silfra Cathedral?+
The fissure is about 20 m deep at its deepest point, but the maximum allowed depth for a dive in Silfra is 18 m. The section runs roughly 100 m from end to end, and its walls rise from the floor to within 30 cm of the surface, so most of the dive is spent far above either figure.
How far can you see in Silfra Cathedral?+
From the entrance you can see all the way to the far end of the section, around 100 m, which silfra.org describes as the longest recorded underwater visibility anywhere in the world.
Sources
- The different sections of Silfra — silfra.org
- Silfra's location — silfra.org
- Silfra — Wikipedia
- Dive Site Silfra in Þingvellir National Park, Iceland — DIVE.IS
Photo credits
- Snorkelers glide single file through Silfra's narrow, moss-lined fissure walls. by Jens Bludau, CC BY-SA 3.0, via Wikimedia Commons
In The Logbook
- Why things look bigger underwaterOcean science · 12 min read
- How far you can see underwaterOcean science · 12 min read
- Why you get cold diving, even in a wetsuitBody & health · 8 min read
- Cold-water diving: is it worth the drysuit?Cold water · 8 min read
- Freshwater diving: lakes, springs and quarriesFreshwater · 15 min read
More dive sites in Silfra
The narrowest water in Silfra, both walls within reach at once
The fissure opens into a hall floored with car-sized boulders
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