Strýtan Hydrothermal Cones
Overview
Strýtan is one of those dive sites that feels like it should not exist. Rising from the dark floor of Eyjafjörður in northern Iceland, these hydrothermal chimneys are geological formations of global rarity — the only known shallow-water geothermal vents in the world accessible to divers. Similar structures exist along mid-ocean ridges in the deep ocean, but at depths of thousands of metres where only submersibles can reach. At Strýtan, the top of the main cone sits at just 15 metres, placing one of the planet's most extraordinary geological phenomena within reach of a certified recreational diver. The main Strýtan chimney rises approximately 55 metres from the seafloor at 70 metres to its summit at 15 metres, a towering column of mineral deposits built up over some 11,000 years by water heated to 72 degrees Celsius deep in Iceland's volcanic bedrock. As this superheated freshwater meets the 3-degree Arctic seawater, dissolved minerals precipitate instantly, adding fraction by fraction to the cone's mass. The visual effect is mesmerising: shimmering curtains of warm water billow upward from vents on the cone's surface, distorting the light like a desert mirage turned vertical and underwater. I descended onto the summit of Strýtan on a still July morning, and the experience remains one of the most surreal of my diving life. The cone's surface is textured with white and rust-coloured mineral crusts, dotted with small vents that release streams of hot water you can feel through your drysuit gloves. Cod and wolffish patrol the cone's flanks, and sea anemones and starfish colonise the mineral surface. A smaller cone called Arnarnesstrýtan lies closer to shore at 15 to 25 metres and offers an equally atmospheric dive with better light penetration. Diving Strýtan requires advance planning and the right operator. The site is a protected nature reserve, and all dives are conducted through the Strytan Divecenter in the village of Hjalteyri, operated by Erlendur Bogason, who has dedicated decades to studying and protecting these formations. Diver numbers are strictly limited to prevent damage to the fragile mineral structures. Akureyri, Iceland's northern capital, is a 20-minute drive away and offers domestic flights from Reykjavik. The water temperature ranges from 2 to 8 degrees depending on season, and a drysuit with appropriate thermal protection is mandatory. Strýtan is diving at the intersection of geology, biology, and wonder — a site that reminds you how much of this planet remains astonishing.
Marine life
Dive profile
DEPTH PROFILE
DEPTH PROGRESSION & WAYPOINTS: Strýtan Hydrothermal Cones
Location
Frequently asked questions
What exactly are the Strýtan hydrothermal cones?
Strýtan consists of underwater chimneys built from mineral deposits left by hot geothermal water venting from the seafloor. The main cone rises approximately 55 metres from a depth of 70 metres, with its summit at around 15 metres. These structures formed over approximately 11,000 years as dissolved minerals in the 72-degree vent water precipitated upon contact with cold seawater. They are the only known shallow-water hydrothermal cones in the world, as similar formations elsewhere occur at extreme ocean depths.
Do I need technical diving certification for Strýtan?
The summit of the main Strýtan cone at 15 metres is accessible to Advanced Open Water divers with drysuit experience. However, exploring the base of the cone at 70 metres requires full technical diving certification with trimix capability. Most recreational divers visit the summit and upper sections, which offer the most dramatic venting activity. A smaller cone called Arnarnesstrýtan is located closer to shore at depths of 15 to 25 metres and is more accessible for recreational divers.
How do I arrange a dive at Strýtan?
Strýtan is a protected nature reserve, and diving is only permitted through the sole authorised operator, Strytan Divecenter, run by Erlendur Bogason in the village of Hjalteyri near Akureyri. Advance booking is essential as the number of dives permitted per day is limited to protect the fragile formations. The divecenter provides all necessary equipment including drysuits. Akureyri, northern Iceland's largest town, is served by domestic flights from Reykjavik.
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Data Provenance
This profile is compiled from 3 operator submissions and 142 community logs. Key facts (depth, entry) are verified against official hydrographic charts.