Gruta das Agulhas: A Secret Treasure on Terceira Island

Travel 13/05/2025

Travel

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5 months ago

Copywriter

Rita Puga

Photos

Bruno Ázera

Gruta das Agulhas is an impressive lava tube in the Porto Judeu (in Angra do Heroísmo), on Terceira Island. This unique geological formation is approximately 250 meters long and reaches a maximum height of 5.4 meters. It is a fascinating testament to the volcanic activity that has shaped the island over the years.

Contents hide

1.1 Formation & Geological Features

1.2 History: Discovery & Exploration

1.3 Fauna & Flora

2 Plan Your Visit to Gruta das Agulhas

2.1 How to Get to Gruta das Agulhas

2.2 Accessibility & Pro Tips

2.3 Where to Eat

2.4 Where to Stay

3 Nearby Attractions

3.1 Refugo Natural Swimming Pool

3.2 Miradouro da Cruz do Canário

3.3 Salga Bay

4 Complementary Information

4.1 Best Season to Visit the Azores

4.2 How to Get to the Azores

4.3 Travel Essentials

4.4 Useful Tools & Apps

What is Gruta das Agulhas

Bruno Ázera | Enjoy the view over the ocean from Gruta das Agulhas

Formation & Geological Features

Gruta das Agulhas is a fascinating volcanic lava tube located in Porto Judeu, on the island of Terceira in the Azores. The eruption of the Pico do Refugo volcano formed it when lava flows reached the eastern coast of Baía do Refugo. As the lava moved towards the sea, the outer surface cooled and solidified, while the interior continued to flow, creating a lava tube.

This natural process resulted in several galleries, with the main one being the Gruta das Agulhas. The cave is named after the secondary mineral formations of opal, which are needle-shaped crystals ranging from 0.2 cm to 0.5 cm in length, adorning the cave’s walls and ceilings. The cave also showcases four distinct levels of lava flows, creating lateral benches of rare beauty. The impressive structure and geological formations of Gruta das Agulhas provide a captivating glimpse into the volcanic history of Terceira Island.

History: Discovery & Exploration

Gruta das Agulhas was first explored in 1967 by the speleological association ‘Os Montanheiros’. It was identified and documented as having its extent and unique characteristics. During the explorations, infrastructure was installed to facilitate access and provide lighting within the cave. However, the erosive action of the sea damaged these structures, leading to the restriction of public access for safety reasons.

Fauna & Flora

Gruta das Agulhas is also notable for its rich biodiversity. It houses several troglobiotic species, including Pseudoblothrus vulcanus, Macarorchestia martini, and Pseudosinella ashmoleorum, as well as endemic species such as Phthiracarus falciformis, Orchestia chevreuxi, and Pseudosinella azorica. This biological diversity gives the cave high ecological and scientific value.

Plan Your Visit to Gruta das Agulhas

How to Get to Gruta das Agulhas

The journey from Angra do Heroísmo to Gruta das Agulhas is approximately 14 km. You can travel by car, motorcycle, taxi, or bicycle. The recommended route is along the EN1-1A and EN1-2A roads, which Google Maps indicates as the best route. The trip takes about 21 minutes by car, 54 minutes by bike, or approximately 3 hours on foot.

→ Find directions here!

Accessibility & Pro Tips

Currently, access to the Gruta das Agulhas is restricted, requiring authorization and specialized technical guidance. Preserving this site is crucial for maintaining its fragile ecosystems and geological formations. They encourage visitors to respect environmental conservation guidelines when exploring the region.

Where to Eat

Click on the following link to find a place to eat near Gruta das Agulhas, in Porto Judeu. 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, Booking, and Trivago. Here, you’ll find the ideal place to stay and enjoy your visit!

Nearby Attractions

Refugo Natural Swimming Pool

Explore Terceira | The magnificent natural swimming pool

Located in Refugo Bay, in the parish of Porto Judeu, just 2.5 kilometers from Ponta das Contendas, the Refugo Natural Swimming Pool is a unique seaside destination. Once used by fishing boats as a beach, it was later transformed into a swimming area. Today, it stands as one of the island’s most popular coastal spots.

This semi-natural pool is suitable for both children and adults, with an average water temperature of around 22°C during the summer months. The area offers excellent amenities for visitors, including a play area, showers, a bar, and toilets. It is a Blue Flag beach and also recognized as an Accessible Beach.

Related Articles: Ponta das Contendas | Biscoitos

Miradouro da Cruz do Canário

The Azores’ archipelago is renowned for its breathtaking viewpoints, and Terceira Island is no exception. One of the must-visit spots is Miradouro da Cruz do Canário, a peaceful perspective offering spectacular views of the Atlantic Ocean and the Islet of Cabras. From here, you can enjoy panoramic views of the island’s coastline. Additionally, on clear days, the island of São Jorge is also visible in the distance.

Salga Bay

For those who enjoy swimming and sunbathing by the sea, Salga Bay is the perfect destination. Located in the village of São Sebastião, Salga Bay features: Salga Beach and the Salga Natural Swimming Pool, which are particularly popular among younger visitors.

Did you know?

This bay was the site of the famous Battle of Salga in 1581. When the people of Angra resisted Spanish rule by releasing bulls to drive out the invaders. For two years, Terceira was the only independent Portuguese territory.

Salga Bay boasts a spacious grassy solarium, two pontoons with stairs leading to the sea, and a semi-natural swimming pool with excellent facilities like parking, accessible pathways, a bar, showers, and toilets. This Blue Flag beach is a safe and welcoming destination, perfect for a relaxing day by the ocean.

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 to São Miguel (PDL), Terceira (TER), Faial (HOR), Pico (PIX), and Santa Maria (SMA) available. 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

The Gruta das Agulhas is one of Terceira Island’s hidden treasures, combining geology, biodiversity, and history in a single location. Its discovery and preservation highlight the importance of protecting the Azores’ natural heritage, not only for scientists but for everyone seeking authentic natural wonders.

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.

FAQs

Where is Gruta das Agulhas located?

Gruta das Agulhas is located in Porto Judeu, on the island of Terceira in the Azores archipelago. It is renowned for its impressive geological formations and natural beauty.

Is Gruta das Agulhas open to the public?

Yes, Gruta das Agulhas is open to the public, but access requires prior authorization and specialized guidance. It is essential to follow safety and environmental conservation guidelines.

What are the main attractions of Gruta das Agulhas?

Gruta das Agulhas’s main attraction is its unique geological formations, such as stalactites and stalagmites. The cave is also well-known for its “needles” (opal crystals) adorning its walls and ceilings.

What is the best time to visit Gruta das Agulhas?

The best time to visit Gruta das Agulhas is during spring and summer when the weather is milder and conditions for exploration are ideal. However, visits require authorization, so it’s essential to check availability before planning your trip.

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Monte Brasil: A Masterpiece of Nature in Terceira

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.