Sung Sot Cave: The ‘Surprising’ Story Behind Halong Bay’s Largest Cave

Of all of Halong’s caves, Sung Sot cave is the largest, perhaps the most renowned, and likely the most visited of all.

Have you already seen our post about the top caves in Halong Bay worth visiting? If so, you will surely understand our fascination with these extraordinary formations. We actually think a few of them are beautiful enough to be featured among the top 20 tourist attractions of the Halong Bay area!

Among the 1,969 sunken limestone towers submerged in the indigo waters of Halong Bay are a series of ancient caves and grottoes – many of which remained unexplored. To date, there are 59 caves listed on the official registry (this includes the most recent discovery of 23 ‘new’ caves), all of which have a special belonging in Halong Bay’s distinctive ecosystem. Undoubtedly the most famous of them all is Sung Sot Cave, which has rightfully earned its near-legendary status among visitors to the world-famous bay.

Experience Sung Sot Cave’s Majesty In The Best Way!

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Thousands of visitors every year flock to Halong Bay to wander through Sung Sot Cave


Largely considered to be the center of Halong Bay, Sung Sot Cave is located on Bo Hon Island, a close neighbor of several other famous attractions such as Titov Island, Bo Nau Grotto, Me Cung Cave and Luon Cave.

Bo Hon Island is one of the largest in the area, its resident cave is also comparatively large. Located on the same island is Trinh Nu Cave, another example of the folklore that Halong Bay is laden with (if you fancy reading about the estranged lovers whose tragic story ended in Trinh Nu Cave with a dramatic death you can read about that here).

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It’s hard to imagine from the outside what is held beyond that tiny entrance

History & Formation of Sung Sot Cave

Sung Sot Cave was allegedly first discovered by the French in 1901, who took it upon themselves to name it “Grotte des Surprises”, or Surprising Cave, because of its ‘surprising’ beauty (although the name didn’t catch on until a good 40 years later). The cave welcomed its first visitors in 1993, a mere one year before Halong Bay would receive its first bestowment of World Heritage site status from UNESCO.

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A corner of Sung Sot cave – the biggest cave in Halong Bay

From 520-470 million BC, Halong Bay was subject to intense tectonic plate movements, along with severe rainfall and flooding which caused the formation of underwater mountains. Millions of years on, the Halong Bay area began to experience a period of extreme heat and drought.

The change in weather patterns is what eventually contributed to the emergence of the thick limestone formations that we can still see today. The steady erosion of these sea mountains eventually delivered to us the much-coveted caves of Halong Bay. The advancement of the sea and its effects on the formation of the caves can be seen on the ceilings, where a ripple-like pattern is often visible.

What You’ll See at Sung Sot Cave

There’s a small dock at the bottom of Bo Hon Island, where you’ll dismount your boat and begin the climb up 100 or so steps to the mouth of Sung Sot Cave. The cave covers a staggering 10,000 square meters (that’s twice the size of the White House if that’s anything to go by). The cave is about 30 meters high and sports a 500-meter long passage (good news for the claustrophobics among us).

The interior is separated into 2 caverns, the first of which is a small amphitheater type of space connected by a small passageway to the larger cavern next door, which is big enough to hold 1,000 people or more. The entire cave is bestrewn with stalactites and stalagmites, which serve as endless material for the legend and ‘lore of the area.

More actractions of Halong Bay Area

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Multi coloured lights illuminate the formations inside Sung Sot Cave


Appointing recognizable shapes, animals, and patterns to the formations within the caves has become a much-loved tradition within Halong Bay, and Sung Sot Cave is no exception. A generous stretch of the imagination is needed in a lot of cases, but it’s part of the fun of the expedition- and if you have a good tour guide who knows their stuff it will make all the difference.

During your trip to Sung Sot Cave, you are likely to be told that one of the stalactites greatly resembles a horse and a long sword (maybe if you squint, like, really hard…). You see it? Yes, of course you do… That horse and sword belong to the legend of Thanh Giong (Thanh can be translated to Saint in English) who is a pretty famous figure in Vietnamese folklore, who left these items here to protect Halong Bay from evil demons.

Among the other ‘recognizable’ formations in Sung Sot Cave are mammoths, elephants, seals, flowers, and even a general gathering his troops.

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Whether or not your imagination stretches far enough to see a mammoth, it’s hard not to be captivated by this place

How to Get There

The best way to see Halong Bay has always been by boat. Among the numerous cruise companies that tour through the bay, a pretty large amount will visit Sung Sot Cave. Get in touch with us if you want to book a cruise visiting Sung Sot Cave!

Sung Sot Cave Facts

The cave was first discovered in western culture in 1901 by French travelers when Vietnam was part of French Indochina. The travelers were so astounded by the sheer size of the cavern that they named it “Grotte des Surprises” or the “Cave of Surprises”.

Beautiful cave with almost 600 steps

Unlike the more documented Sung Sot Cave, Thien Canh Son is relatively smaller, and far less crowded with visitors, yet does not lack anything in terms of structure and things to see.

Sung Sot cave (Suprise Cave) – One of the most beautiful caves in Halong bay. Sung Sot means surprise in Vietnamese. The unique name of this cave originates in 1901.

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