Dark and Bright Cave

Located in the emerald waters of Lan Ha Bay, Vietnam, lies a hidden gem that is both mysterious and enchanting. The dark and bright cave, also known as Hang Sang Toi in Vietnamese, is a natural wonder that attracts adventurers seeking an unforgettable experience.

This cave offers a unique adventure for visitors where they can explore two different chambers with contrasting features. The first chamber is pitch black and requires visitors to use torches or flashlights to navigate through stalactite and stalagmite formations. However, the second chamber is illuminated by natural light, which filters through the limestone cliffs, creating a surreal atmosphere. This rare combination of darkness and brightness creates an otherworldly experience for those who dare to venture into this mystical cave.

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Explore the mysterious Dark and Bright Cave




Dark and Bright Cave is located inside Lan Ha Bay, an extension of Halong Bay. Thanks to its favorable location, this cave and lake surrounded by mountains bear the outstanding features of two bays: the unique geological features of cave in HaLong Bay and the diversity of the Cat Ba archipelago.

Besides, there are so many things to see in the surrounding area, such as Sung Sot Cave, Cat Ba National Park, or Van Boi Beach.


The Beauty of a Dark and Bright Cave


Explore Dark and Bright Cave leads to the “wonder world,” where tourists can see a blend of sea, mountains, sky, and plants all together. Its breathtaking scenery will make you forget all your fatigue after a long journey to get there.

Located right next to the famous Surprise Cave, but half hidden underwater, Dark and Bright Cave has its own pristine features to attract tourists.

Visitors will shortly be overwhelmed by the miraculous stalactites created by water snails from the cave ceiling due to the condensation of limestone over millions of years. The fossils of fresh water with different sizes bring uniqueness and diversity of shapes. These freshwater snails look like bamboo shoots growing in the middle of a mysterious forest.

The Dark & Bright Cave is a combination of two, as its name suggests, Dark Cave and Bright Cave. The Dark Cave lives up to its name with its pitch-black interiors and eerie atmosphere that can be explored by flashlight. However, as it’s mostly underwater for the whole year, visitors might find it hard to visit this particular cave.

Dark Cave
Dark Cave is underwater for most of the time

In contrast, the Bright Cave is a surreal world where sunlight pours through openings on the roof and illuminates the turquoise-blue waters below. It’s much larger compared to the Dark Cave, with a height of 3m, a width of 4m, and a length of 100m.

The size of Bright Cave depends on tidal fluctuations. Rarely has the sea flooded to the ceiling of this cave; this place is open for visitors to explore. The Bright Cave is also significantly shorter than the Dark Cave and has tons of natural light shining through the cracks and holes in the rock, making it feel like a church “molded” by Mother Nature herself.

Visiting these caves offers a glimpse into different facets of nature’s wonders, from darkness to light. The dark cave features narrow passages laden with stalagmites and stalactite formations, while visitors can kayak or swim in brightly lit waters inside the bright cave and marvel at unique rock formations formed over millions of years.

After getting out of Dark and Bright Cave, visitors will meet a huge green sea valley surrounded by magnificent mountain, an ideal place for water-based activities like swimming or snorkeling.

Green Sea Valley
Sea Valley revealed after escaping Dark & Bright Cave 

Photo by woong hoe in Pixabay

Extra tips: As the cave might be fully covered by water during a specific time of year, ask your tour operator in advance to make sure you won’t miss out on this wonder!

What to do in Dark & Bright Cave


If you come to Dark and Bright Cave, here are some activities you should not miss:


Kayaking or bamboo boating to explore the cave


Kayaking is a must if you’d like to visit Dark and Bright Cave. The altitude of the cave is quite low, making it impossible for a big cruise ship to enter. As a result, sailing on your own with a kayak or having someone experienced guide you through the caves on a bamboo boat would be quite a unique experience.

kayaking in Dark and Bright Cave
Kayaking is a must when visiting Dark & Bright Cave

As you glide through the Dark Cave on your kayak or bamboo boat, you’ll be surrounded by stunning rock formations that have been sculpted over centuries. The eerie darkness adds an extra element of excitement as you navigate your way through narrow passages and around sharp corners. The silence is only broken by the sound of your paddle cutting through the water, creating ripples that reflect off the cave walls.

On the other hand, kayaking or bamboo boating in bright caves offers a completely different experience. As you float along on this traditional vessel made from natural materials, sunlight streams around you from openings high above.


Admire the fanciful stalactites in the cave


Nature’s magnificent stalactites will undoubtedly astound you. They dangle from the cave’s roof directly above your head. During less congested times, you may even observe swarms of bats hovering beneath the dome. As a result, the Dark and Bright Cave is also known as the Bat Cave.


Visit the green valley hidden in the cave


Going through the Dark and Bright Cave, you will discover a green valley in majestic limestone mountains. You will be amazed by the beautiful scenery, like in paradise. Stop rowing by letting the boat float along the water, breathe in the fresh air, and feel the peace between rivers, clouds, and mountains. This will be the moment to help you release all the stress of the hustle and bustle of city life. Coming here, you will be immersed in the most unspoiled nature.



Visiting Cua Van floating village


In the Dark and Bright Cave area, you can find some famous fishing villages where fishermen live in harmony with nature, exploiting the natural potential and conserving marine life.

Cua Van fishing village is one of them. Located right next to Dark & Bright Cave, the village was inhabited thousands of years ago and is home to around 700 residents who mainly earn their living through fishing.

Cua Van Village
Cua Van Village among most beautiful village of the World by Journeyetc.com

Visitors have the opportunity to explore this unique way of life by taking a boat tour through the fishing village. Here you can witness firsthand how the locals work together to cast their nets into the water, haul fish onto their boats, or repair their nets onshore. A visit to Cua Van provides an authentic glimpse into traditional Vietnamese culture that is otherwise hard to find in modern cities.


Watch the sunset over the sea


On the way out of the line in the afternoon, you might see the romantic sunset over the sea. The poetic scenery of mountains, rivers, and moored yachts provides a poetic scene that makes you bewildered by the beauty of the sunset.

Sunset in Halong Bay
Photo by Kévin JINER on Unsplash


How to get there


As Dark & Bright Cave located in Lan ha Bay, an extension part of Halong Bay, you’ll have to travel there first. Here’s are our detailed guide about Halong Bay transportation. 

Once getting to Halong Bay, The only way to get to Dark and Bright Cave is by cruise. Normally, an overnight cruise would be an ideal option, as besides Dark and Bright Cave, these cruises will take you to explore other famous destinations in the surrounding area. However, if you’re tight on time and budget, a day cruise could also help you explore this beautiful wonder.

In order to take the day cruise, the first step is to reach Cat Ba Island. You can take a ferry or speedboat from Hai Phong or Halong Bay directly to Cat Ba Island. Once you arrive at Cat Ba Island’s Beo Wharf, head over to your hotel and book a tour package that includes a trip to Dark and Bright Cave. If you prefer going solo, rent a boat for the day from Beo Wharf and navigate towards Lan Ha Bay yourself.

A day cruise to visit Halong Bay usually lasts from 4 to 6 hours. Boat tour ticket prices range from 500,000 VND per person to 1,000,000 VND per person, depending on the boat or itinerary you choose. A lot of exciting things are waiting for you to discover.

If you’re keen on taking an overnight cruise that covers Dark and Bright Cave, take a look at our collections of Lan Ha Bay Cruises.




The best time to visit


The best time to visit Dark & Bright Cave is from April to July, when the temperature range is from 25 to 30 degrees Celsius. The weather is favorable for water activities like swimming, kayaking, or snorkeling. The sky is also quite clear during this time, and if you’re lucky, you might have a chance to see a magnificent sunset in the area.

lan ha bay during summer months
The entire area is sunny during summer months

Extra tips: Be aware that there will be occasional rain and typhoons, especially during June and July, so check your forecast before planning. 

For further information, here’s our weather guide of Halong Bay



In conclusion, the dark and bright cave in Lan Ha Bay is a unique natural wonder that offers visitors an unforgettable experience. The contrast between darkness and light creates an ambiance of magic and mystery that lures tourists from all over the world. The stalactites and stalagmites formations within this cave are a sight to behold and make for excellent photo opportunities.

Exploring the cave’s intricate paths requires some effort, but it’s well worth it once you emerge on the other side. So, if you’re planning a trip to Vietnam, make sure to add the dark and bright cave in Lan Ha Bay to your itinerary for an adventure you won’t soon forget!



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