1. Home
  2. Halong Bay
  3. Halong Bay Travel Guide
  4. Sung Sot Cave: Halong Bay’s Grotto Of Surprises

Sung Sot Cave: Halong Bay’s Grotto Of Surprises

Colourfully lit large cave

In the center of the picturesque Halong Bay, hidden among the imposing rock formations, lies one of the most magical and awe-inspiring caves in the world…

A relatively small, seemingly unassuming opening in a limestone cliff leads into a series of immense caverns, replete with myriad mythical rock monoliths resembling fairytale figures, and natural architecture that would make Gaudi blush. It’s impossible to wander through the stalactite sentries lining the cathedral-like halls of this cave, gazing up at the stalagmite chandeliers, and not feel a sense of amazement and wonder.

The History of Sung Sot Cave

Halong Bay lies on the north-eastern coast of Vietnam, close to the country’s border with China. This area contains many incredible limestone caverns, and Sung Sot cave is widely considered the crowning jewel.

Sung Sot cave is located on Bo Hon Island, close to other popular natural attractions such as Titov Island, Trinh Nu Cave, Luon cave, and Tam Cung Cave.

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”.

It was given the Vietnamese name “Sung Sot” which means “amazing feeling” or “thunderstruck”. Locals say this is because of the way light, reflected into the cave by moving water from outside, caused the limestone rock formations inside the cave to appear alive – bestowing a feeling of dumbstruck awe on any who visited the cave.

For many years the cave was very difficult to reach and was visited by only the most intrepid explorers, but the designation of World Heritage Site by UNESCO in 1994 and improvements to infrastructure meant that many more people were able to visit Sung Sot cave. Today it’s a popular place to visit, not only en route of cruise boats but also on the itinerary of many adventures in Vietnam.

Golden lit stalagmite

Beautiful stalagmite

Why is Sung Sot Cave Shaped So Strangely?

Halong Bay contains predominantly limestone bedrock, and the bay is an example of limestone karst topography. Karst landscapes are formed when rainwater containing carbonic acid picked up from the carbon dioxide in the atmosphere dissolves the soluble bedrock over millions of years. This forms cracks, hollows, and caves, which are then exacerbated by running water passing through them. Many different types of caves are formed in this way, and Sung Sot cave is an example of an old phreatic cave.

This karst landscape, combined with unique plate tectonic action when the whole area was under the sea during the Ordovician and Silurian periods (500-410 million years ago) formed the very unusual and artistic-looking monolithic islands jutting from the ocean in Halong Bay.

The rising and falling of sea levels in the past 20 million years hollowed out many of these mountains, creating caves like Sung Sot and the incredible rock formations they contain. Ancient flowing water formed the mesmeric, artistic rippling patterns we find on the ceilings and walls of the caves, evoking images of velvet theatre curtains, or perhaps a cloud-strewn sky.

Mother Nature’s Sculpture Exhibition

Bo Hon is one of the largest islands in Halong Bay, and the awesome size of Sung Sot cave reflects this – it spans an area of around 10,000 m2. For scope, this cave could easily fit the entire area of the White House in it! The cave reaches a height of around 30m and extends a length of around 500m.

Sung Sot cave is split into two main chambers, firstly you come into a cavern called the “Waiting Room” and then pass through a narrow passageway which opens up into a larger second chamber known as “Serene Castle” or “Grand Opera House”. This is an apt name as the stalactites and stalagmites strewn throughout the cave form beautiful and interesting natural sculptures that look like they could be citizens of a vast citadel, petrified by some magic spell.

The sculptures have been affectionately named by locals and include a Buddha, a large tortoise, human guards, and many more. These are lit by subtle and unobtrusive colored lights that have been installed throughout the cave. Perhaps the most famous of these formations is a massive phallus-shaped rock in the second cave, which is cheekily lit by pink light and viewed by locals as a fertility symbol!

Halong Bay is home to many species of flora and fauna, some of which can be found nowhere else in the world. In the deepest part of the cave, you can emerge into a leafy glade known as “Royal Garden” where lucky visitors might find a group of monkeys collecting fruit and other beautiful wildlife.

Pool in the cave


A Cave Of Myths – Dragons and Saints

It’s difficult not to feel the magic of Sung Sot cave and the surrounding area, and areas of such dramatic beauty around the world always come with fascinating folklore and legends. Letting your imagination run wild while exploring the cave and surrounding area is all part of the fun, and throwing yourself into learning the folk tales of places like this certainly enhances the experience!

Climbing the “100 steps” up to the foreboding entrance does feel like a pilgrimage. The climb up is steep, and dappled shadows dance on the immense paved slabs as the sunlight slants through the leafy jungle foliage overhead.

At the entrance, you can turn around and gaze across the impressive expanding vista of Halong Bay. There are many legends surrounding this area and with a good local tour guide, you will hear many of the stories conjured up by the mystical mountains and caves.

Halong Bay itself means “Dragons Descending”. It is said that to protect the Vietnamese people from invaders, the gods sent dragons as protectors. The dragons expelled jets of jade and jewels from their mouths, which then crystallized and formed the tooth-like islands that litter the bay now. These islands linked together and deceptively submerged and reappeared, forming an impenetrable wall against invading ships, which were dashed to pieces on the magical rocks. After proving victorious, the dragons settled in slumber beneath the ocean until they are called again, and the jade islands became permanent, where they serve as a reminder to anyone wishing to invade the country.

Sung Sot cave is said to be the resting place of one of the Four Immortals of Vietnamese mythology – the “giant boy” Thanh Giong (Saint Giong). Giong is a famous mythical folk hero in Vietnam – a boy who magically grew in size to be a giant, and rode an iron horse leading the Vietnamese people in battle against the Han invaders from China. After this victory, he helped the villagers of Halong Bay chase away demons that were terrorizing the area. Before ascending to heaven, he swore to protect his people forevermore and left his horse and longsword in Sung Sot cave to banish demons, where they turned to stone and keep watch over the bay to this day. You can find these statues inside the cave, and some of the small pools inside the caves are known by locals to be his horse’s footprints.

Knowing these stories really adds to the magic of Sung Sot cave, and as you step through the entrance it’s easy to imagine that you are stepping into another world, where dragons, heroes, and fairytales come to life.

How To Visit

The only way to explore Sung Sot cave and Halong Bay is by boat. A cruise in Halong Bay is recommended as it will incorporate visits to many of the different islands and caves.

Best Time To Visit

Sung Sot cave is an amazing place to visit at any time of year, but it is a lot busier in the peak seasons of June to August where most of the visitors will be Vietnamese and Asian people. It will be busy again from November to January, where most of the visitors will be from Europe and America where the winter temperatures are colder. The humidity is generally lower in the winter months so it may be a better time to visit for people unaccustomed to high levels of humidity. For more information on weather patterns in Vietnam check out our dedicated when to go to Vietnam post.

Prices are generally higher during these peak seasons and availability may be an issue so be sure to book your visit in advance.

Important dates to note when the cave may be much busier are:

  • Tet (Vietnamese New Year, the date varies but it is in January or February)
  • 30th April (Reunification day)
  • 1st May (International Workers’ Day)
  • 2nd September (Independence Day – the cave is often decorated with Vietnamese flags on this day)
  • 25th December (Christmas Day)

At the end of April or the start of May, there is the Halong Carnival which is a street festival organized for travelers and held in Ha Long City, so this may be a great time to visit.

Boats in a small bay

Tour boats at the entrance

Top Tips For Visitors

  • Exploring a cave can be a daunting idea for the more claustrophobic among us, but Sung Sot feels large and spacious so this shouldn’t be a worry.
  • Be prepared for quite a bit of walking, the path up to the cave is fairly steep. However, there will always be staff around to lend a helping hand to those who need it.
  • Be sure to take pictures of Halong Bay from the mouth of the cave, it provides an incredible view of the surrounding area.
  • The cave is generally well ventilated but can be quite hot and humid at certain times of the year, so it is recommended to bring light, airy clothes.
  • Wear good shoes as the caves can be slippery at times, and bring water with you, as the water sold at the cave entrance may be expensive.
  • Be sure to stay with your guide, for safety and also so they can point out all the different named rock formations to you. You can even try finding and naming your own shapes!

Visiting Sung Sot cave is a memory that will stay with you for life. It has been frequently listed in the top ten most beautiful caves in the world and it is certainly easy to see why!


While Rainforest Cruises aim to provide accurate and up-to-date information, we make no representations as to the accuracy or completeness of any information herein or found by following any link on this site. Rainforest Cruises cannot and will not accept responsibility for any omissions or inaccuracies, or for any consequences arising therefrom, including any losses, injuries, or damages resulting from the display or use of this information.

This entry was posted March 23, 2020
As Featured In