The Santorini Volcano: Nea Kameni, Palea Kameni and How to Visit

What and Where

Ask a geologist where the Santorini volcano is and the answer is not the cliff-top villages. The main island of Thera is the rim of a huge collapsed caldera that measures about 12 by 7 km and is up to 385 m deep. The active part is in the middle of that flooded basin: two young volcanic islets, Nea Kameni and Palea Kameni.

Nea Kameni, which means new burnt in Greek, is a nearly round lava dome about 2 km across, built of dacite lava and ash. It is the larger of the pair at 3.4 square km, and it rises from the water in ridges of black rock with no shade and no shops. Its neighbor Palea Kameni, old burnt, is much smaller at 0.5 square km. It formed far earlier, from eruptions between 197 BCE and 47 CE, and Wikipedia notes it was once a private island, bought in 1899 and sold in 1975. A herd of goats lives there, and Wikivoyage counts a church and a single resident.

The islets sit in the same water as Aspronisi, a tiny uninhabited island 650 m long and 200 m wide partly made of white pumice, and across the lagoon from Thirassia, the second-largest island in the group at 9.3 square km. The whole volcanic history of Santorini spans 3.5 million years, and at least 10 major eruptions are documented from 518,000 BC up to the last one in 1950.

One point confuses visitors: you do not walk to a smoking crater lake. What you climb on Nea Kameni are the younger lava domes, including the active sulfur vent named Jorgo, or George, and the main crater Georgios, where fumaroles still vent steam and sulfur with a strong smell.

The Two Islets at a Glance

The table sums up the two Kameni islets: when each formed, how big it is and what visitors actually do there. Sizes come from Wikipedia's Santorini caldera and islet pages, and the formation dates from the same sources. Use it to see how the two islets differ.

The Eruption Record

Nine eruptions have broken the surface on the Kameni islands since 197 BC, when the first Kameni islet rose out of the sea. The Roman historian Cassius Dio recorded another small island emerging in 47 CE. The Minoan eruption, dated to about 1600 BC and rated VEI 7, came long before both: its column rose an estimated 30 to 35 km into the stratosphere and its tsunamis struck the north coast of Crete 110 km away. No human remains have been found at the buried town of Akrotiri, which suggests the residents evacuated before the end.

The table lists the eruptions that matter to a visitor, with the years and the effect of each. The dates for the Kameni eruptions come from Wikipedia's Nea Kameni page, and the dome names from the Greek travel site Nikana.

Is It Active, and How It Is Watched

Yes, the Santorini volcano is active in the scientific sense, but it has not erupted for more than 70 years and scientists class it as dormant. Gas emissions of CO2, SO2 and H2S continue on Nea Kameni, and Nea Kameni is a protected scientific site. A Greek-Italian monitoring station run by ISMOSAV records temperatures from three surface points and from the fumaroles near the summit. ISMOSAV set up the station with the Hellenic Survey of Geology and Mineral Exploration and researchers from Florence University and the Italian National Research Council. CO2 emissions are measured yearly, and infrared and thermal readings indicate the volcano remains dormant.

Two dated earthquake swarms have tested nerves in recent years. A swarm began centered near Santorini, Amorgos, Anafi and Ios, with thousands of quakes. Santorini declared a state of emergency and about 11,000 people were evacuated. Wikipedia reports the swarm showed a connection between the Kolumbo and Santorini magma systems. In an early 2026 sequence, magnitudes ranged from 3.5 to 5.1, scientists classed it as a typical Aegean seismic swarm, no evacuation orders were issued and ferries, the airport and hotels kept running. There are no signs of an imminent eruption. Nobody can say when the volcano will erupt next, and any source claiming a date should be treated with suspicion.

The volcano is not alone out there. Kolumbo, an active submarine volcano about 8 km northeast of Cape Kolumbo, is the largest of about 20 submarine volcanic cones off Santorini. It last erupted in 1650, killing about seventy people on Santorini, and a 2006 NOAA expedition found hydrothermal vents on its crater floor, which lies about 505 m down.

The Path To The Rim

A gravel path leads up to the crater rim on Nea Kameni, and you can walk a full circuit of the rim once you are up there. The Greek national tourism site puts the climb at 20 to 30 minutes. Other sources run from a 1.2 km each way walk to 30 minutes up and 20 minutes down, so plan on about an hour on the island altogether.

Most groups spend only about 10 minutes at the rim itself, where the smell of sulfur and a plume of smoke make it clear the rock is still breathing. The main crater is named Georgios, also written as Jorgo or George, and fumaroles vent steam and sulfur beside a well marked tourist path.

• Gravel path to the rim
• 20 to 30 minutes up, plan about an hour on the island
• Sulfur smell and visible smoke at the rim

The Fee At The Site

The Nea Kameni entrance fee is €5 per person, paid in cash at the site. It is almost never included in the boat ticket, and rangers collect it at the trailhead. Card readers on the island are unreliable, so bring euro notes.

There are reductions for ages 65 and over, students and children 5 to 12, and toddlers and visitors with disabilities go free. Nea Kameni has no shade and no shops, and the lava rock is razor sharp.

Heat, Shoes And What To Bring

The walk is rated moderate, and heat rather than difficulty is the main challenge. July and August are the hardest months because of the sun on bare lava. Closed-toe shoes with grip are advised, along with a hat, SPF 50 or higher sunscreen and at least 500 ml of water per person.

The volcano boat tours that bring you here run from the Old Port of Fira, which you reach by cable car or nearly 600 steps, and from Athinios. Short cruises last 2.5 to 3 hours and standard tours 3 to 5 hours, with a season listed as April through October. A six-hour version adds 30 minutes at the hot springs and 2 hours on Thirassia.

Catamarans and the Landing

One thing to know before booking: the catamaran listings describe no landing on Nea Kameni, so the crater walk and the 5 euro fee do not apply. Some list the Palea Kameni springs or Nea Kameni among their stops, so read the listing. To climb the rim you need one of the dedicated volcano boats, and the Nea Kameni walk is part of a 3-hour volcano cruise run with a maximum of 40 guests.

For the bathing stops and the route the catamarans take instead, see the Santorini hot springs guide and the Santorini caldera page, or compare every catamaran cruise in Santorini on the homepage.

What The Route Looks Like

Catamarans from Vlychada Marina and Ammoudi Bay list Red Beach and White Beach as stops, and some also list Nea Kameni, Palea Kameni or the hot springs. The listings describe no landing on the volcano, no crater walk and no 5 euro fee. That is the difference between a volcano tour on a dedicated boat and a day on a catamaran: you trade the climb for about 5 hours of sailing, food and swimming.

Three Cruises That List The Kameni Islands

The Renieris Classic Catamaran is a 5-hour cruise from Vlychada Marina at $98 per person, with Nea Kameni on its list of stops and an onboard BBQ with unlimited dry white wine. The Sunset Oia Luxury Open Bar caps the group at 20 guests, costs $124 per person and lists Nea Kameni, Palia Kameni and the hot springs among its stops. The Santorini Day Tours Small Cruise leaves Ammoudi Bay for up to 20 guests at $171.79 per person and stops for a swim at the Palea Kameni warm springs.

You can see all of the Santorini catamaran cruises side by side on the Santorini catamaran cruise.

One Paragraph On The Springs

The hot springs sit in a small cove off Palea Kameni, not on the volcano itself. The water is warmer than the surrounding sea and tinted orange and brown by sulfur, iron and manganese, and the swim from the anchored boat is a short open-water distance of roughly 50 meters. Sulfur can permanently stain white swimsuits and silver jewelry.

The Santorini hot springs guide covers the swim in detail.

One Paragraph On The Caldera

The islands you sail around sit inside the Santorini caldera, a flooded crater about 12 by 7 km with cliffs up to 300 meters high on three sides and water up to 385 meters deep. The landscape and how it formed are covered on the Santorini caldera page.