What makes exploring Son Doong a once-in-a-lifetime journey?

Son Doong Cave: The Natural Largest Cave in the World

Son Doong Cave is the world's largest natural cave, hidden deep within the core zone of Phong Nha - Ke Bang National Park in Quang Tri Province (formerly Quang Binh Province). With an estimated volume of 38.5 million cubic meters and a length of nearly 9 kilometers, the cave is truly immense. Its largest chamber rises up to 200 meters and stretches over 150 meters, making it large enough to fit a 40-story skyscraper.

The cave entrance was first discovered in 1990 by Ho Khanh, a local jungle man from Phong Nha, while taking shelter from a storm deep in the forest. After nearly 20 years of searching, he rediscovered the entrance in 2009 and guided the British Vietnam Caving Expedition Team, led by Howard Limbert, to conduct the first survey of Son Doong Cave.

The survey confirmed Hang Son Doong as the world's largest natural cave. The discovery was later recognized by National Geographic in 2009 and officially recorded by Guinness World Records in 2013.

Inside Son Doong Cave is a spectacular underground landscape shaped over millions of years. It features massive stalagmites and stalactites, a mysterious underground river, and a unique ecosystem with its own distinct microclimate. Temperatures inside the cave remain relatively stable, ranging from 18 - 22°C in winter and 22 - 25°C in summer.

Two massive dolines allow fresh air and sunlight to reach deep inside the cave. Doline 1, located 449 meters from the entrance, is where the spectacular sunbeam phenomenon appears. Doline 2 shelters a lush underground rainforest, stretching 252 meters deep and 175 meters wide.

More than 200 plant species and 203 insect species have adapted to this isolated environment. The cave is also home to unique wildlife, including blind fish, albino scorpions, and other cave-dwelling arthropods, alongside towering trees that grow up to 40 - 50 meters tall.

The underground river creates clouds and mist inside the cave, giving Son Doong the appearance of a prehistoric world hidden from the outside.

Under the expedition lights, the cave's enormous chambers gradually come into view. Massive stalactites and stalagmites emerge from the darkness, revealing formations of extraordinary size and complexity, including:

• Giant stalagmites such as the 80-meter-tall Hope and Vision are among Son Doong's most remarkable formations. The towering stalagmite gained international attention when Good Morning America host Ginger Zee delivered a live morning broadcast from the cave to more than 30 million viewers.
• At Doline 1, 449 meters from the entrance, Watch out for Dinosaur is illuminated by a dramatic shaft of sunlight. Nearby, the Wedding Cake stalagmite completes one of Son Doong's most spectacular natural light displays.
• Doline 2 is home to a lush underground rainforest that spans nearly 175 meters across. Often shrouded in mist, it resembles a hidden Garden of Edam deep beneath the surface.
• The Passchendaele Passage stretches for more than 400 meters. During the wet season, its crystal-clear stream glows like jade, while in the dry season, the passage is covered with mineral-rich mud.
• The 90-meter-high Great Wall of Vietnam marks one of the expedition's final challenges. Formed by layers of flowstone, its surface shimmers like a cascading waterfall when illuminated by headlamps.

What makes the USD 3,000 Son Doong Expedition worth the price?

The Son Doong Expedition costs approximately USD 3,000 per person. The price includes VAT, entrance fees, forest environmental service fees (USD 600), and national park management and monitoring fees (USD 20). The expedition's value goes far beyond access to the world's largest cave. It combines a once-in-a-lifetime adventure with professional operations and strict conservation standards to protect this extraordinary natural wonder.

A safe expedition route designed by cave exploration experts

Son Doong Cave lies deep within the core zone of Phong Nha - Ke Bang National Park, surrounded by rugged mountains and dense jungle. Reaching the cave requires crossing challenging terrain, including steep forest trails, underground rivers, dolines, and areas with unique microclimates.

Throughout the expedition, travelers trek a total of 25 kilometers over forest and mountain terrain with a cumulative elevation change of around 800 meters. Inside the cave, the route includes a 90-meter entrance descent, rocky slopes, underground rivers, and other natural obstacles.

The Son Doong expedition route was designed by the cave experts who led the first surveys of the cave in 2009. For example, Mr. Howard Limbert, Mrs. Debora Claire Limbert, Mr. Martin Holroyd, etc.

Years of exploration and field research have given the team an in-depth understanding of the cave's terrain, underground rivers, and seasonal conditions. This expertise ensures that every river crossing, rope climb, and technical section is carefully planned and carried out with appropriate safety equipment.

Travelers explore the world's largest cave on a route designed by the people who know Son Doong best. Every stage of the expedition is planned with the safety of both travelers and the expedition team as the highest priority.

A professional support team ensuring a safe expedition

Each Son Doong expedition is limited to just 10 travelers and supported by a team of around 28 staff. The team includes 1 guide, 1 cave expert, 6 safety assistants, 2 chefs, and 18 porters.

Throughout the journey, the guide, cave expert, and safety assistants accompany travelers every step of the way. They share insights into the cave, the expedition, and local culture while providing technical guidance and ensuring safety throughout the expedition.

Behind this team is a comprehensive training and operational system built around strict safety standards. Guides, cave experts, and safety assistants receive professional training in first aid, rescue techniques, and other essential expedition skills. They also undergo regular skills assessments, and only those who meet the required standards are qualified to lead the expedition.

Oxalis Adventure also uses internationally certified safety equipment, with most gear imported from leading manufacturers in France, the United Kingdom, and Switzerland. All equipment is regularly inspected and maintained to ensure it meets strict safety standards.

Porters are responsible for carrying travelers' luggage, food, camping equipment, and all expedition supplies entirely by hand. They are local people with extensive knowledge of the jungle terrain and follow a separate route to ensure everything arrives at the campsites on schedule. Travelers rarely see the porters along the trail. However, they are welcomed with freshly prepared meals at lunchtime, fully set up campsites each evening, and their luggage waiting upon arrival.

High-quality service with a strong commitment to conservation

The campsites inside the cave are equipped with individual tents, insulated sleeping platforms, mattresses, seasonal sleeping bags, changing areas, and environmentally friendly toilets. Drinking water is filtered on-site using a dedicated filtration system. All dining equipment and utensils are thoroughly cleaned and sterilized with boiling water after each use.

Meals are freshly prepared and served hot throughout the expedition. They are made with fresh ingredients and cater to different dietary preferences, including vegetarian meals. The menu is carefully planned to provide balanced nutrition. All food waste, human waste, and other waste are removed from the forest. They are then processed following strict environmental procedures.

A limited expedition with only 1,000 travelers each year

The Son Doong Expedition is limited to just 1,000 travelers each year, with a maximum of 10 travelers per tour. This strict limit helps protect the cave's fragile ecosystem and supports long-term sustainable tourism.

The Son Doong Expedition Tour is more than a journey to one of the world's most famous caves. It offers travelers a rare opportunity to experience nature on its own terms. From its immense scale to its extraordinary geology and fragile ecosystem, every part of the cave leaves a lasting impression. Equally important is Oxalis Adventure's commitment to conservation. Through strict operating standards, the expedition allows travelers to explore this natural wonder while helping protect every stream, tree, and living habitat within it.

The USD 3,000 price is more than the price of an adventure. It reflects the value of a rare expedition, professionally operated with a strong commitment to conservation and long-term benefits for the local community.

6-day, 5-night Son Doong Expedition Itinerary

Operated by Oxalis Adventure, the Son Doong Expedition Tour is a world-class adventure that lasts 6 days and 5 nights. The journey includes 4 days and 3 nights of jungle trekking, cave exploration, and camping inside Son Doong.

The detailed itinerary is outlined below:

Day 1: Transfer from Dong Hoi to Phong Nha and mandatory safety briefing

• Travelers arrive in Dong Hoi before 3:00 PM and are transferred to Phong Nha.
• At 5:00 PM, the group explores the Phong Nha Caves Exploration Museum to learn about the 35-year journey of cave exploration in the region.
• Travelers will attend a mandatory safety briefing at Oxalis Home. They sign a liability waiver and have their trekking shoes and backpacks checked by the guide to ensure they meet safety requirements.
• The group then enjoys dinner together and gets to know one another before the expedition. Afterward, travelers return to the hotel for a good night's rest before the adventure begins the next day.

Day 2: Explore Ban Doong Village, Hang En Cave and camp in the forest

• After breakfast, the group meets before 8:00 AM and travels to Km35 on the western branch of the Ho Chi Minh Road, the starting point of the expedition.
• The group treks downhill along Ba Gian Pass (Doc Ba Gian) for about one hour to enter the primary forest, then continues through the forest for another 30 minutes to reach Doong Village, home to the Bru-Van Kieu ethnic community. Here, travellers learn about the isolated community living in the core zone of Phong Nha-Ke Bang National Park.
• The group continues deeper into the core zone to reach the entrance of Hang En Cave. From the front entrance, travellers trek about 700 metres into the cave, wading through a stream and climbing over rugged rocks scattered naturally down the slope from the large entrance, where shafts of sunlight fall onto the underground lake. The group stops for lunch inside the cave, surrounded by its distinctive cinematic scenery. After lunch, they trek through Hang En Cave and continue towards the entrance of Son Doong Cave.
• In the afternoon, travellers arrive at the first campsite in front of the entrance to Son Doong Cave. The group settles into their tents, freshens up, has dinner, and enjoys the peaceful atmosphere of the primary forest surrounding the world’s largest cave.

Completing the first day of the expedition marks an important physical milestone before the journey continues.

Day 3: Explore the upper level and begin the journey into Hang Son Doong

• The expedition team starts the day by enjoying the peaceful morning in the primary forest and having breakfast.
• Travellers begin the journey with a 700-metre-long upper section of the cave, featuring magnificent stalactite formations above Hang Son Doong Cave.
• After having lunch at the cave entrance, the guide provides the necessary safety equipment before travellers abseil down into Hang Son Doong.
• The journey continues with several challenges, including crossing an underground river, climbing over large rocky slopes, and trekking across sand hills to admire the Hand of Dog stalagmite and the otherworldly light filtering through Doline 1.
• At around 4:00 PM, the group arrives at the Doline 1 campsite, where they settle into their tents and rest.

Day 4: Explore Hang Son Doong - Watch out for Dinosaurs - Garden of Edam

• After breakfast at Doline 1 campsite, the group begins another day of exploration. The route passes through challenging terrain to Watch out for Dinosaurs, with the chance to witness the spectacular sunbeams at Doline 1.
• In the afternoon, travelers climb rocky slopes toward Doline 2 and explore the Garden of Edam and the dark passage beyond. Along the way, they encounter magnificent cave formations and cave-adapted species such as blind fish, blind spiders, and albino scorpions.

Day 5: Climb the Great Wall of Vietnam and exit Son Doong Cave

• The group has breakfast at the Doline 2 campsite before putting on the necessary safety equipment and harnesses to climb the Great Wall of Vietnam.
• The route passes through the Garden of Edam and crosses the Passchendaele Passage. Travelers cross by inflatable raft when water levels are high or walk across mineral-rich mud during the dry season before reaching the base of the Great Wall of Vietnam.
• One by one, travelers climb an 18-meter ladder, followed by a 70-meter rocky slope with a 45-degree incline.
• After exiting Son Doong Cave, the group treks through the forest to the pickup point. A cold beer or soft drink awaits to celebrate completing the expedition to the world's largest cave.

The return transfer takes travelers to Chay Lap Farmstay, arriving at approximately 3:00 - 4:00 PM.

Day 6: Relax at Chay Lap Farmstay and explore Chay Lap Village

• Travelers enjoy breakfast at Chay Lap Farmstay before spending the morning at their own pace. They can cycle through Chay Lap Village or go kayaking or SUP at Chay Lap Riverside.
• Check-out is at 12:00 PM. Oxalis then provides a transfer to Dong Hoi Airport or Dong Hoi Railway Station. Travelers may also choose to extend their stay and continue exploring Phong Nha independently.

Physical requirements for the Son Doong Expedition

To ensure a safe and successful 6-day, 5-night expedition, travelers must meet the following physical requirements:

• Age: 18 - 70 years old.
• Trekking Experience: Within the past 12 months, travellers must have completed at least one overnight trekking and camping trip through forests, mountains, rocky terrain, and steep slopes, covering at least 8 km per day with an elevation gain of 1,000 m.
• Fitness level: Travelers should be able to run 5 kilometers continuously in under 45 minutes and climb five flights of stairs without experiencing shortness of breath or dizziness. Regular training for 36 months before the expedition is strongly recommended.

Travelers are also required to provide an honest medical declaration, including any history of heart disease, asthma, joint problems, high blood pressure, or claustrophobia. Those who exercise regularly and have previous trekking experience are generally better prepared for the physical demands of the expedition.

How to book the Son Doong Expedition

The Son Doong Expedition is currently fully booked through the end of 2027. Bookings for 2028 are now open, and places are filling quickly. Travelers are encouraged to reserve their spot well in advance to secure their preferred departure date and allow enough time to prepare physically for the expedition.

To join the Son Doong Expedition, travelers must book through the official Oxalis Adventure website. After selecting a departure date, they can click "Book Now" to begin the reservation process.

Travelers are then asked to complete a health declaration and provide details of their trekking experience. The Oxalis team reviews each application to confirm that the physical requirements are met. Once approved, travelers receive a confirmation email with payment instructions to complete the booking.

How to get to Son Doong Cave

Round-trip transfers between Dong Hoi Airport or Dong Hoi Railway Station and Phong Nha are included in the Son Doong Expedition.

Travelers can fly directly to Dong Hoi Airport from Hanoi or Ho Chi Minh City. Those traveling from Hanoi or nearby destinations such as Hue, Da Nang, Ninh Binh, and Ha Long can also reach Dong Hoi by train, coach, or private transfer. Some private transfer services also travel directly to Phong Nha.

For more detailed travel information, travelers can refer to the guide: How to Get to Son Doong Cave.

What to pack for the Son Doong Expedition Tour

Because the expedition involves several days of trekking through the jungle and exploring caves, travelers should prepare a few essential personal items to ensure both comfort and safety throughout the journey.

Equipment provided by Oxalis Adventure

To support a safe and comfortable expedition, Oxalis Adventure provides most of the equipment needed throughout the Son Doong tour. This allows travelers to focus on the experience without carrying unnecessary gear.

Safety and exploration equipment:

• Helmet and headlamp for cave exploration
• Trekking gloves
• Safety harness and support ropes for steep sections
• Life jackets for underground river crossings

Camping equipment:

• Personal tents at the campsites
• Insulated sleeping mats and mattresses
• Seasonal sleeping bags

Expedition support:

• Luggage storage at the Oxalis office
• Personal water bottle
• Energy snacks for trekking
• Basic first-aid kit
• 15L dry bag for personal belongings
• Porters who transport luggage to the campsites

Personal items travelers should prepare

Travelers should prepare personal items suitable for multi-day trekking through the jungle and camping inside the cave, including:

Clothing:

• 3 - 4 long-sleeved, quick-drying trekking shirts
• 2 - 3 pairs of stretchy trekking pants
• A warm jacket for colder weather
• Warm clothing for winter and lightweight, breathable clothing for summer evenings at the campsite
• Swimwear for those who wish to swim in the underground river

Footwear and trekking accessories:

• Closed-toe trekking shoes with good grip. Waterproof or quick-draining shoes are recommended; trekking boots are not required.
• 4 pairs of high, thick socks to protect against leeches and reduce foot discomfort
• Sandals, strap sandals, or outdoor sandals for use at the campsite
• A 20 - 25L personal backpack for carrying essential items during the trek

Personal items:

• ID card or passport
• Personal medication if undergoing medical treatment
• Towel, toothbrush, and toothpaste
• Sunscreen, sunglasses, and hat
• Waterproof pouch for phone and camera
• Power bank with a capacity of around 20,000mAh or less

Additional recommended items:

• Multifunctional scarf
• Insect repellent
• Blister prevention patches for feet
• Foot powder to reduce moisture and prevent discomfort during trekking

Safety guidelines and important notes for the Son Doong Expedition

Safety is the top priority throughout the Son Doong Expedition. Travelers are required to follow these important guidelines:

• Attend the mandatory safety briefing before the expedition.
• Follow instructions from guides, cave experts, and the safety team at all times.
• Do not separate from the group or explore independently.
• Use safety equipment properly: Wear and use helmets, harnesses, and headlamps throughout rope sections, underground river crossings, and cave exploration.
• Protect personal health: Provide accurate medical information before the tour and immediately inform the guide if experiencing fatigue, dizziness, or difficulty breathing during the expedition.
• Protect the environment: Do not leave waste in the forest or cave. Avoid touching cave formations, stay within marked routes, and do not step on fragile cave ecosystems.
• Prepare mentally: Follow all safety procedures, sign the liability waiver, and be ready for challenging terrain, including high rope sections, river crossings, and dark cave passages.