Algar do Carvão: Inside a Volcano in the Azores

Travel 09/09/2025

Travel

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2 months ago

Copywriter

Melissa Masvaleix

Photos

Bruno Ázera

Photos

Álvaro Palácios

Imagine being able to visit the inside of a volcano. ‘Impossible!’ you might think. Well, in the Azores, everything is possible. Indeed, Algar do Carvão in Terceira Island provides a once-in-a-lifetime experience with its open crater. In this post, we will learn everything you need to know about the fascinating cave. Lace your walking shoes, and let’s go on this unique adventure!

Contents hide

1 What is Algar do Carvão

1.1 Geology & Volcanology

1.2 History & Geography

1.3 Culture & Festivities

1.4 Fauna & Flora

2 What to Do at Algar do Carvão

2.1 Enter the Cave

2.2 Explore the Inside of Algar do Carvão

2.3 Go to the Lake

2.4 Back to the Visitor Center

3 Best Time to Visit Algar do Carvão

3.1 Best Season

3.2 Best Time of the Day

4 Plan Your Visit to Algar do Carvão

4.1 How to Get to Algar do Carvão

4.2 Where to Eat

4.3 Where to Stay

4.4 Pro Tips & What to Bring

5 What to Do Around Algar do Carvão

5.1 Visit Gruta do Natal

5.2 Walk Around Angra do Heroísmo

5.3 Relax at Biscoitos Natural Pools

5.4 Stop at Serra do Cume Viewpoint

6 Video

7 Complementary Information

7.1 Best Season to Visit the Azores

7.2 How to Get to the Azores

7.3 Travel Essentials

7.4 Useful Tools & Apps

8 Conclusion

9 Photo Gallery

10 Map

What is Algar do Carvão

Algar do Carvão is a 90-meter-deep volcanic chimney in the central group of islands in the Azores archipelago. It was formed about 3,200 years ago due to several eruptions. Nowadays, Algar do Carvão is a tourist highlight not to be missed when visiting Terceira. All year round, many travelers from all over the world venture into the earth’s depths from this cave, recognized as a Regional Natural Monument.

Geology & Volcanology

Mónica Jardim | It's impossible not to be amazed by being inside a volcano, literally. Algar do Carvão — Mónica Jardim | It’s impossible not to be amazed by being inside a volcano, literally

The cave was created after the magma drained from the chimney and flowed back into the chamber. The first big eruption leading to Algar do Carvão is known as Pico Alto. It occurred North of the Guilherme Moniz volcanic complex and spread lava far away. However, later, a basaltic eruption created the strombolian volcano Pico do Carvão and the current Algar as we know it today, including the lake area.

Algar do Carvão is a true geological wonder. Thanks to its uniqueness, it gained international scientific fame and is now a significant Geosite of the Azores Geopark.

History & Geography

Bruno Ázera | A fantastic photo that details the shape of this volcanic chimney

The first explorers, Cândido Corvelo and José Luís Sequeira, entered the cave in 1893. In 1934, Didier Couto created the profile of Algar do Carvão. At that time, the only way to explore it was to use a rope.

Organized descents to the cave began only in 1963, thanks to the association still in charge of this place: Os Montanheiros (The Mountaineers). This group of local enthusiasts revealed the beauty of Algar do Carvão to the world and initiated construction to facilitate easier access and thorough exploration of the cave.

As visiting the cave would have taken a whole day at that time, they decided to open a 44-meter-long tunnel in 1966 and build the current 300-meter-long staircase in 1977. This natural monument is situated in the central area of Terceira, within the vast volcanic formations that comprise the island. The total area of Algar do Carvão is 40,5 acres.

Culture & Festivities

Representing a tremendous natural stage perfect for echoing music, Algar do Carvão has already hosted several live concerts by popular national bands. For instance, in 2017, the group Fado Preto Fado Branco performed beautiful traditional Fado songs. Algar do Carvão has hosted not only musicals but also cultural and religious events, such as the celebration of the Eucharist. This place also attracts many TV reporters for documentaries.

Fauna & Flora

Alvaro RP | The top of the volcano chimney is now fully covered by flora. Algar do Carvão — Alvaro RP | The top of the volcano chimney is now fully covered by flora

Algar do Carvão may appear inhospitable for life, but a closer look reveals that it is home to many bird species. Mostly at night, it is possible to spot sparrows, common blackbirds, and chaffinches. Occasionally, you can also see rabbits that fell off the crater edge, and of course, many arthropods (insects).

In terms of flora, the cave shows an abundance of vegetation in the green crater walls. Between the plants, you can find Macaronesian holly, Erica azorica, Azores laurel, Azores blueberry, and ferns. There is also ivy, carex, brown wort, and many types of mosses and liverworts. Deeper down, only some ferns, Bryophyta, and diatoms are surviving the darkness.

What to Do at Algar do Carvão

You can visit Algar do Carvão all year round for about 30 minutes of exploration. It is definitely something to add to your must-sees on Terceira Island. Nowadays, there is light and an indicated path for a safe visit. A maximum of 150 people is allowed inside the cave at a time, but no booking is required. You can purchase your ticket at the entrance.

Enter the Cave

Alvaro RP | Tourists walking around the Algar do Carvão — Álvaro RP | Tourists walking around the Algar do Carvão

When you enter the visitor center, you will go down the stairs and cross the tunnel to the inside of Algar do Carvão. There are 338 steps in total connecting the different balconies. The floor is concrete, so it is an easy walk. The chimney is the only source of natural light inside the cave. It is the perfect spot to take beautiful pictures of the famous crater, which is surrounded by lush vegetation.

Explore the Inside of Algar do Carvão

Andreia Azevedo | View from the top of the volcano over the interior

Welcome to the underground wonderland! Inside Algar do Carvão, it is like walking on another planet. Nothing resembles our world. There are impressive stalactites, which serve as evidence of the eruption that gave rise to the cave.

If you continue straight, you will find the Boca dos Enganos, which is a dead end. There are also some restricted access areas for research and preservation purposes. Look around and find the magnificent whitish walls with some red veins. The rocks are rich in ferric and silica minerals, and you can also see some basalt layers.

Go to the Lake

jwhatx | Photo of the lake in the bottom of Algar do Carvão — @jwhatx on Instagram | Photo of the lake at the bottom of Algar do Carvão

At the bottom of the 90-meter-deep chimney lies a lake with crystal clear waters. The lake is mainly filled with rainwater, so the depth varies according to the seasons. It can reach depths of up to 15 meters and diameters of 400 square meters. During the years with little rain, the lake can become almost dry.

Researchers once found a perfectly preserved fossil of a seabird covered in silica at the bottom of the lake. The lake in Algar do Carvão is beautiful, but you can only see it from a distance. Note that swimming in the lake is forbidden.

Back to the Visitor Center

After visiting all the parts of the cave, it is time to return to the visitor center. Look around one last time and climb the 80-meter elevation. The center is small, but a construction project for a new center with a budget of 1.5 million euros is underway. It will be significantly larger — 900 square meters — and will focus on educational exhibitions to raise awareness of this vital natural treasure.

Best Time to Visit Algar do Carvão

You can visit the Algar do Carvão every month of the year. However, there are some significant differences you should be aware of to choose the right time to explore the cave.

Best Season

During the off-season, the cave is only open on certain days of the week. If you are visiting Terceira for only a couple of days, ensure Algar do Carvão is open during your stay. So, summer is the best season for more flexibility. However, in the summer, the cave can get a bit crowded, as there are more tourists than in the other seasons.

Best Time of the Day

If you want to have the place to yourself or with a few people, the best time to visit is during the opening hours. How amazing can it be to stroll inside a volcano on your own? For the most light, around midday is probably your best bet. However, when the sun sets, the golden light creates a unique atmosphere.

Plan Your Visit to Algar do Carvão

In this section, we’ll share tips on how to make the most of your time and enjoy every moment of Algar do Carvão. Keep reading for the best tips.

How to Get to Algar do Carvão

The volcanic cave of Algar do Carvão, located at an altitude of 640 meters, is situated in the middle of the island of Terceira. It belongs to the Porto Judeu parish, located 12 km north of Angra do Heroísmo city. Access is relatively easy and well-marked. However, you need a car to get there, as there is no public transportation to Algar do Carvão. Therefore, your best options are to rent a car, go on a guided tour, or take a taxi.

Where to Eat

Click on the following link to find a place to eat near Algar do Carvão. It will take you to TripAdvisor, where you can review the 10 best restaurants.

Where to Stay

Searching for the perfect place to stay? We’ve made it easy by filtering top accommodation options from Airbnb and Booking. Here, you’ll find the ideal place to stay and enjoy your visit!

Pro Tips & What to Bring

At the reception of Algar do Carvão, please ensure you have some cash, as the mobile network is unstable and may affect card payments.
An essential thing to remember is that collecting geological samples is forbidden. Take nothing but pictures. Regarding photos, tripods are not permitted inside the cave.
According to their official website, visiting Algar do Carvão is not recommended for babies or lap children. They also don’t recommend that pregnant ladies at an advanced stage of pregnancy enter the cave. If you are traveling with someone who has physical limitations, please notify reception upon arrival before entering the cave.
As the floor inside Algar do Carvão is often wet, suitable footwear, such as walking boots or sneakers, as well as a raincoat, is highly recommended.
The average temperature inside the cave is 12°C to 13°C, making it quite cold. Bring appropriate clothing to keep you warm.

What to Do Around Algar do Carvão

Visit Gruta do Natal

Pulga no Passaporte | As in Algar do Carvão, you will find many flora species inside the wonderful Gruta do Natal

When visiting Algar do Carvão, you can buy a combo ticket to explore Gruta do Natal (“Christmas Cave” if translated literally). In 2022, the double ticket costs 12 euros per adult; as of January 1, 2023, it will be 15 euros for the two caves.

Each cave is thoroughly different, and both are worth visiting. While Gruta do Natal is smaller, the visit is a bit longer. In fact, you will have a briefing at the reception and will be given a helmet to enter the cave. Inside, there are two staircases, and you can walk on the original floor, not concrete ground. Access is a bit more complicated, but it provides a great experience that is closer to nature.

Walk Around Angra do Heroísmo

David Rodrigues | The narrow streets of Angra do Heroísmo

Angra do Heroísmo is the largest city on Terceira, with a population of approximately 10,000 inhabitants. It is characterized by the famous green peninsula of Monte Brasil, located just behind the town, as well as its lovely, narrow streets and colorful houses.

Angra was classified as a World Heritage by UNESCO in 1983. It is so lovely to stroll around and learn more about its rich history through monuments and museums. Among the museums, if you wish to learn more about the geology and volcanology of the island, don’t forget to visit the Volcano Speleological Museum, owned by the Montanheiros Association.

Relax at Biscoitos Natural Pools

João Santos | Amazing drone shot over the Biscoitos natural pools. Algar do Carvão — João Paulo Santos | Amazing drone shot over the Biscoitos natural pools

The natural pools at Biscoitos, located on the north coast of Terceira Island, are the perfect spot to lay your towel and soak up the sun. Locals and travelers love it there. There are several pools to swim and snorkel in, as well as some spots to jump from the volcanic rocks. The crystal-clear water is ideal for swimming all year round, with the warmer months being August and September.

Stop at Serra do Cume Viewpoint

Bruno Ázera | The viewpoint of Serra do Cume is one of the most famous photographic spots in Terceira island — Bruno Ázera | Serra do Cume Viewpoint is one of the most famous photographic spots in Terceira

Serra do Cume is probably the most famous viewpoint in Terceira and one of the most famous in the Azores archipelago. From there, you can see a good part of the island and the ocean. Don’t forget to take pictures from the wooden platform with the view of the green fields, typical of the Azores.

Video

Complementary Information

Best Season to Visit the Azores

The Azores Archipelago boasts a unique climate that shapes its lush landscapes, making it a splendid year-round destination. With mild temperatures and minimal fluctuations, each season offers something unique. Spring averages 16 °C, summer reaches 21 °C, autumn cools to 18 °C, and winter remains mild at 14 °C.

How to Get to the Azores

The Azorean Archipelago is easily accessible through numerous flight routes. Lisbon and Porto are the main entry points to the continent, with direct flights available to São Miguel (PDL), Terceira (TER), Faial (HOR), Pico (PIX), and Santa Maria (SMA). To find the best flight, use search engines like eDreams or Skyscanner. These platforms enable you to compare prices and schedules from various airlines in one convenient location.

For more details on how to get to the Azores, take a look at our complete guide. But what if you want to explore beyond your arrival island? We’ve got you covered!

→ Once you’ve found the perfect route, book your tickets and get ready to experience one of the world’s most stunning island groups!

Travel Essentials

Useful Tools & Apps

The weather in the Azores can be variable, so it’s helpful to use some apps before visiting the islands. Spotazores provides live camera feeds from the main tourist attractions, allowing you to check the weather and plan your visit. For accurate weather predictions, use Windy or Windguru — they provide the most reliable predictions.

Conclusion

Algar do Carvão, a protected reserve since 1987, receives thousands of visitors every year from all around the globe. It is actually the most visited cave in the Azores, with 60,000 entries in 2019. If this magical place was not on your list of places to visit in Terceira, you definitely need to add it now.

Authors’ Note

I am pleased to inform you that all the recommendations in this article are based on my personal experience and observations. As the author, I have personally visited each attraction mentioned, ensuring that every suggestion is grounded in first-hand knowledge and genuine enthusiasm.

Photo Gallery

rolhas_e_aventuras. Algar do Carvão — rolhas_e_aventuras

josklijs. Algar do Carvão — rolhas_e_aventuras

Map

Miradouro do Castelo Branco: White Castle on a Volcano in Azores

Impactful & unforgetable experiences

Browse all the outstanding experiences you can live in the Azores

Whale Watching

Lying in the middle of the mystical Atlantic Ocean, the wonderful Azores islands are a permanent home or point of passage for more than a third of the entire world’s whale and dolphin species.
Dive into this lifetime adventure with ancestral creatures where science and emotion come together at their highest level!
This may be the best place on earth to observe these magnificent animals.

Jeep Tours

Feel the rush, surprise, and emotion in an all-terrain vehicle, this adventure will take you to the core of secrets. We will take you where nobody has ever reached before. Experience moments of adrenaline in our jeep tours. The adventure through the interior of the islands will begin!
The trips are made in 4×4 vehicles properly equipped, capable of taking you to places little explored. It is intended for those who want to discover new perspectives and unusual scenarios on the Azores Islands in a more adventurous way. We pass on secondary roads, which are not usually found on the usual tourist routes. They are narrow paths, dirt paths, called “canadas” in Azorean, and are mostly used by farmers.

Kayaking & SUP

Find solace in listening to the birds chirping and enjoy the peacefulness of the moment, and make sure you capture it with your camera this unforgettable experience.
Sete Cidades is a volcanic complex where you can visit several lakes. Inside one of the craters, you can find two lakes, known as Lagoa Verde (green lake) and Lagoa Azul (blue lake), that feature in a legendary love legend about the lake’s creation. This special place was elected as one of the country’s seven natural wonders and once you are there, you will definitely understand why.
The contrast of colors between the two mysterious lakes is mesmerizing, and being on the water, in the middle of the volcanic crater, will give you a different perspective of the high green cliffs around.

Canyoning

The boldest and most unique adventure! Heading through the natural landscape you will be able to enjoy some adrenaline-fueled activities. Wet, wild, and absolutely unforgettable.
This experience involves trekking through river gorges, around pools, or even behind waterfalls.
Canyoners navigate down waterways by abseiling down waterfalls, clambering over rocks, or jumping into water rock pools. You will get wet for sure, even with an exposure suit, but this is not too bad with the relatively warm climate of the Azores.

Van Tours

Take a seat in the emotion sector, stop wherever you want and where your curiosity demands it. Taste, observe, and treasure the entire originality of this Atlantic paradise.
If you want to get to know the island of São Miguel more peacefully, without the worry of renting a car, opt for more comfort, on a pleasant van ride. Make the most of your vacation and get away from the city.
This way, you are guaranteed to know the main points of interest, but also those you will not find in travel guides. This is perhaps the best choice for those looking for convenience and security.

Hiking Tours

From lush green vegetation to a great variety of wildlife, enjoy heaven after a long ramble with otherworldly vistas.
Enjoy your holidays in the Azores walking through the beautiful landscapes of volcanic origin. Breathe fresh air and contemplate all the diversity of fauna and flora you will find.
You can start the day feeling the nature among mountains, enjoy more than one lagoon on the island of São Miguel, and finally, to end the day in a perfect way, take a boat trip to see the sunset.

Bike Tours

In order to discover São Miguel island and stay active, cycling is definitely the way to go!
At Sete Cidades volcanic complex, have one of your best bike adventures! Indeed, we are not taking you to a random place. We are talking here about one of the Seven elected wonders of all of Portugal.
This is where our awesome bike adventures take place and we can tell that we love to take our guests there!

Coasteering

Here, you can explore the geography of the giant rocky cliffs climbing through the sky and how the pounding waves smooth the coastline. Coasteering is an exhilarating experience combining rock and water activity with coastal landscapes. It was originated as a combination of mountaineering and orienteering.