In Bai Tu Long Bay, the emerald waters and towering limestone mountains are not the only sights, but deep within are hidden caves where nature has carved masterpieces over millions of years. These caves are galleries of stalactites and stalagmites, natural cathedrals of limestone pillars, and mysterious lagoons only accessible by kayak.
At Viet Sails Boutique, caving is done at a thoughtful pace. Small group sizes mean you don’t have to jostle in crowded lines. Our knowledgeable guides will share both geological information and local legends. The itinerary includes caves that are rarely visited by large tour groups.
Here is a complete guide to the caves you will explore on the 2D1N and 3D2N itineraries with Viet Sails.
Difficulty: Moderate (approximately 100 stone steps to the entrance)
Time needed: 45-60 minutes, including viewing platform
Thien Canh Son Cave is often called the jewel of Bai Tu Long Bay. The journey begins with a climb of around 100 well-maintained stone steps that wind up the limestone cliffs. Each twist and turn opens up sweeping views of the bay below, revealing a glimpse of the spectacular panorama that awaits you at the top.
As you enter the cave, a rush of cool air greets you, providing a pleasant relief after the tiring climb. Inside, your eyes gradually adjust to reveal a vast cavernous chamber decorated with thousands of stalactites hanging from the ceiling like chandeliers and stalagmites rising from the ground in cream, rust and grey limestone columns.
What makes Thien Canh Son so special:
Over time, through the talented hands of nature, the stalactites have formed beautiful images such as lotus flowers, flowers or animals,… each stalactite gently sparkles under the cleverly arranged lighting to highlight but not overwhelm the natural beauty. Your tour guide will share about the geological processes that have created these stalactites over millennia and the local folk tales that have woven them through generations.
But the real highlight of this cave lies outside. The 360-degree panorama of Bai Tu Long Bay from this height, with limestone peaks stretching to the horizon, emerald waters dotted with traditional fishing boats, and winding beaches hidden in the distance, will always leave visitors in awe. This is one of the most photographed scenic spots in the bay for good reason.
Location: Accessed via day boat on Day 2 (3D2N)
Difficulty: Easy (minimal climbing required)
Time needed: 60-90 minutes including kayaking
Thay Cave is only featured on Viet Sails’ 3-day, 2-night itinerary, making it a compelling reason to opt for the longer itinerary. To enter the cave, you need to transfer to Viet Sails’ smaller boat, which can navigate the shallower waters around the cave entrance. As you approach, the cave entrance appears as a dark crevice at the foot of a towering limestone cliff, partially obscured by vegetation.
Inside Thay Cave:
The cave’s interior reveals a fascinating cave system with stalactites in various stages of formation. Many of them are shaped like brushes, inkstones, study tables, and even at the end of the cave there are small, discreet classroom-like chambers, earning the name “Thay Cave”. Your guide will introduce and point out where the mineral-rich water has created colored veins in the limestone: rusty orange from iron oxide, green from copper compounds, dark gray from manganese.
Natural light filters through the gaps in the cave ceiling, creating impressive beams of light, illuminating the limestone particles suspended in the air. The movement of light and shadow changes constantly throughout the day, combined with the sound of flowing water to create a magical, charming and mysterious space.
Water element:
What makes Hang Thay different is the opportunity to participate in underwater activities immediately after exploring inside the cave. The waters around the cave entrance are calm, clear and perfect for kayaking around the cave, exploring smaller caves and hidden corners that visitors cannot reach by road.
The area is currently very deserted. Most days, your Viet Sails group will likely be the only visitors, allowing you to truly explore instead of just a tourist presentation in crowded spots.
Location: Cap La Island area and various anchorage points
Difficulty: Easy to moderate depending on conditions
Time needed: Included in kayaking sessions (60-90 minutes)
Some of Bai Tu Long’s most magical caves are inaccessible on foot – you have to paddle through them. During kayaking sessions at Cap La Island, you can explore small caves and tunnels carved through the limestone by thousands of years of waves. Paddle in the dark for 10-20 seconds, then enter secret lagoons completely enclosed by vertical limestone walls – nature’s own private swimming pools. The contrast between the dark rocks above and the bright turquoise water creates an otherworldly beauty.
Safety and instruction:
Viet Sails staff ensure a thorough safety briefing before kayaking. We will be close enough to assist but still give you the freedom to explore. We will show you which passages are safe to enter (tides and weather conditions are important), point out the best angles for your shots and can identify the marine life you can see in the crystal clear waters. Bring a waterproof case for your phone and camera, allowing you to capture these moments without worrying about dropping your electronics in the bay.
Important footwear: Wear closed-toed shoes with good grip. Cave floors can be slippery due to moisture and water seepage. Flip-flops are not suitable for climbing Thien Canh Son as they can be slippery.
Bring a small flashlight or headlamp: Although lighting systems are available in larger caves, they are limited to protect the atmosphere. A separate light source helps you see details in dark areas and is essential in less developed caves.
Protect your camera from humidity: If you are using a camera, bring a microfiber cloth to wipe away any mist from the lens. Consider using a waterproof case or at least a sealed plastic bag. The transition from hot outdoor air to cool air inside a cave can cause condensation to form on the lens immediately.
Respect the formations: Never touch stalactites or stalagmites. The oils from your skin will inhibit their growth. Also, you are not allowed to break off pieces of stalactites as souvenirs as this is both environmentally damaging and illegal.
Watch your head and your steps: The ceiling can be low in some places, and the floor is uneven. Be aware of your surroundings to avoid bumping and tripping.
The caves of Bai Tu Long Bay are more than just fascinating geological discoveries to highlight on a cruise. They are reminders of the depths of time, evidence that nature operates on scales beyond human comprehension, and spaces where silence is almost sacred. On a Viet Sails cruise, you will spend hours inside these limestone caves. Sometimes it is an organized exploration with a guide, sometimes it is drifting in a kayak with only the trickle of water for company.
Sail beyond the surface. Discover what millions of years can sculpt from stone and water. Book directly through our website to instantly start to plan for your trip right here.
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