Dark Cave Phong Nha: Complete Adventure Guide 2025 (Zipline, Mud Bath & Entrance Fees)

What is Dark Cave?

Dark Cave (Hang Toi) in Phong Nha Ke Bang National Park, Quang Binh Province (Quang Tri), is Vietnam's ultimate adventure cave experience. Unlike other caves in the region that feature artificial lighting and easy boardwalks, Dark Cave lives up to its name where you will get to explore 5.5 kilometers of pitch black caves equipped only with a headlamp, swim through underground rivers, and immerse yourself in a natural therapeutic mud bath deep inside the cave. Add Vietnam's longest zipline (400 meters across the stunning Chay River), kayaking, and swimming, and you have one of the most thrilling destinations in Central Vietnam. 

This complete Dark Cave Phong Nha guide 2025 covers everything you need: entrance fees , opening hours, how to get there from Phong Nha town, what activities are included, essential packing tips, and whether to book a tour or go independently. Discovered in 1990 and opened to tourists in 2014, Dark Cave also served as a bomb shelter during the Vietnam War, adding historical significance to its natural beauty. 

Whether you're an adrenaline junkie or simply want a unique cave experience beyond the typical tourist trail, Dark Cave is a must visit destination that combines adventure, nature, and history in one unforgettable day trip.

Why Visit Dark Cave in Phong Nha?

It's an adventure playground, not just a sightseeing spot. You'll zipline 400 meters across the emerald Chay River (Vietnam's longest zipline), kayak through calm waters surrounded by limestone cliffs, swim through underground rivers, and wade through complete darkness with water up to your chest. This isn't a passive tour where you just take photos like a tourist but you're actively exploring!

The natural mud bath is truly unique. Deep inside the cave, you'll find a chamber filled with thick, mineral-rich therapeutic mud. Slather yourself in it, float effortlessly in the underground pool, and rinse off in the cool cave water. It's equal parts hilarious and relaxing, and you won't find anything like it elsewhere in Vietnam

You'll feel like a real explorer. Without artificial lights or paved paths, Dark Cave gives you an authentic sense of discovery. As you navigate through narrow passages, duck under stalactites, and feel your way along the cave walls, you understand what early adventurers experienced when they first entered these underground worlds.

It combines nature, adventure, and history. The cave served as a bomb shelter during the Vietnam War, offering protection to locals from air raids.

Perfect for active travelers. If you're tired of tourist-heavy attractions and want something that gets your adrenaline pumping, Dark Cave delivers. It's especially popular with backpackers, adventure seekers, and anyone who prefers doing over just looking.

Dark Cave Entrance Fee & Ticket Prices 2025

Dark Cave offers two ticket packages:

Full Access Package: 450,000 VND (~$19 USD)

 Includes:

• 400-meter zipline across Chay River
• Full cave exploration with headlamp
• Natural mud bath inside cave
• Kayaking on Chay River
• Swimming and water activities
• All safety equipment (helmet, headlamp, life jacket)
• Locker (50,000 VND refundable deposit)
• Insurance

Restrictions:

• Minimum height: 1.3m (4'3")
• Weight: 40-90 kg (88-198 lbs) for zipline

Limited Access Package: 250,000 VND (~$11 USD)

Includes: Kayaking, swimming, water obstacle course
Excludes: Zipline, cave exploration, mud bath 

Children's Tickets

• Children (1.0m-1.3m): 150,000 VND (~$6 USD)
• Under 1.0m: Free

Where to buy: At entrance (cash), online (GetYourGuide, Klook), or through your Phong Nha hotel/homestay

Dark Cave Opening Hours & Best Time to Visit

Operating Hours

Daily: 7:30 AM - 4:00 PM (last entry at 3:00 PM)

The full Dark Cave experience takes approximately 2.5-3 hours from start to finish, including the zipline, kayaking, cave exploration, mud bath, swimming, and return journey. If you arrive after 1:30 PM, you might feel rushed and may not have time to fully enjoy all the activities.​

Important timing notes:

• Ticket sales typically stop between 3:30-4:00 PM depending on the season and how busy they are
• During the rainy season (October-February), the cave sometimes closes earlier if water levels rise too high
• Always call ahead during rainy season to confirm the cave is open for all activities

Best Time to Visit (By Season)

Dry Season: March - September (BEST TIME) 

This is when Dark Cave is at its absolute best. The Chay River is calm and crystal-clear, all activities are guaranteed to operate, and the mud bath is at the perfect consistency (not too watery from rain). The weather is hot and sunny, which actually works in your favor since you'll be wet for most of the experience anyway.

Best months: March, April, and September offer the sweet spot—warm weather without the peak summer heat and fewer tourists than the May-August rush.

What to expect: Temperatures range from 28-35°C (82-95°F). It gets hot, especially when ziplining and kayaking under direct sun, but once you're in the cave, it's refreshingly cool at around 18-20°C.​

Rainy Season: October - February (Visit with Caution) 

You can still visit Dark Cave during rainy season, but be aware that activities may be limited or cancelled if it's been raining heavily. The cave can partially flood, the zipline may close during storms, and the mud bath can become too watery.

Advantages: Fewer crowds, potentially lower prices, and the cave formations glisten with extra moisture.

Disadvantages: Unpredictable closures, colder water temperatures (can be uncomfortable), and limited visibility if there's been flooding.

Mini tip: If you're visiting during rainy season, check weather forecasts and contact Dark Cave directly (or ask your hotel) to confirm operations before making the trip.​ 

Best Time to Visit (By Time of Day)

Early Morning (7:30-9:00 AM): HIGHLY RECOMMENDED

Arriving right when they open gives you the best experience. You'll beat the tour buses that typically arrive around 10:00-11:00 AM, meaning shorter queues for the zipline, more personal space in the cave, and better attention from staff. The morning light is also perfect for photos of the Chay River and surrounding limestone mountains.

Mid-Morning (9:00-11:00 AM): Still Good

A decent compromise if you're not an early riser. Moderate crowds, and you'll still finish in time to visit another cave in the afternoon (many people combine Dark Cave with Paradise Cave or Phong Nha Cave in one day).

Midday (11:00 AM-2:00 PM): Busiest and Hottest

This is when most organized tours arrive. Expect long waits for the zipline (20-30 minutes), crowded kayaks on the river, and a packed cave entrance. The sun is at its strongest, making the outdoor portions uncomfortably hot.

Afternoon (2:00-3:30 PM): Fewer People, But Rushed

If you don't mind a condensed experience, afternoon visits mean fewer crowds. However, staff may hurry you along to ensure everyone finishes before closing time. You might not get to fully relax and enjoy the mud bath or swimming.

My recommendation: Arrive at 8:00-8:30 AM during the dry season (March-June) for the perfect combination of good weather, manageable crowds, comfortable temperatures, and plenty of time to enjoy every activity without feeling rushed or feeling like a typical tourist!

How to Get to Dark Cave from Phong Nha Town

By Motorbike (15-20 minutes) - RECOMMENDED

Cost: 100,000-150,000 VND/day (~$4-6) to rent, or free if you've already rented one

Duration: 15-20 minutes from Phong Nha town

Difficulty: Easy as you drive on a straight road with clear signage 

Parking: Free at Dark Cave visitor center

Why I recommend it: This is hands down the best option if you're comfortable riding a motorbike. You have complete freedom over your schedule, can arrive early to beat crowds, and easily combine Dark Cave with other nearby attractions (Paradise Cave is 24km further south, Phong Nha Cave is 16km south).

Directions:

1. From Phong Nha town center, head north on Road QL1A toward Dong Hoi
2. Stay on QL1A for about 16km (you'll pass rice fields and small villages)
3. Look for the large "Dark Cave" or "Hang Toi" sign on your right
4. Turn right and follow the access road to the parking area (about 1km)

What you need:

• International Driving Permit (technically required, though rarely checked)
• Helmet (provided by rental shop, but check condition)
• Basic motorbike riding skills as the QL1A highway can have heavy traffic at times

Where to rent: Virtually every hotel, hostel, and travel agency in Phong Nha town rents motorbikes. Most common are semi-automatic Honda Waves (100,000-120,000 VND/day) or automatic Honda Visions/Yamaha Janus (150,000-200,000 VND/day).​

Mini tip: Rent the bike for the full day and visit Paradise Cave on the way back. Many travelers do both caves in one day: Dark Cave early morning, lunch in Phong Nha town, then Paradise Cave in the afternoon.

By Guided Group Tour:

Cost: 500,000-700,000 VND (~$21-30) for full-day package including transport, entrance fee, and lunch

Duration: Hotel pickup around 8:00-8:30 AM, return 4:00-5:00 PM

What's included: Round-trip transport in air-conditioned minibus, English-speaking guide, Dark Cave entrance fees, all equipment (helmet, headlamp, life jacket), lunch at a local restaurant, and sometimes combined with Phong Nha Cave or Paradise Cave visit.

Best for: Travelers who don't ride motorbikes, prefer hassle free experiences, or want a guide to explain the history and geology.​

How to book: Through your hotel/hostel in Phong Nha town, or online via GetYourGuide, Klook, or Viator (booking online is usually 10-20% more expensive but guarantees availability).

Pros: No driving stress, meet other travelers, guide provides context, convenient hotel pickup/drop-off

Cons: Fixed schedule (less flexibility), may wait for other passengers, group moves at average pace (faster explorers may feel held back)

By Private Car or Taxi:

Cost: 300,000-500,000 VND (~$13-21) round trip from Phong Nha town

Duration: 15-20 minutes each way

Best for: Families, small groups (3-5 people), or travelers who want comfort and flexibility without riding a motorbike.

How to arrange:

• Grab app (most reliable and transparent pricing)
• Ask your hotel or homestay to arrange a private car with driver
• Negotiate directly with taxi drivers in Phong Nha town

Two options:

1. One-way drop-off + pickup later: Negotiate a time for the driver to return (usually 3-4 hours later). Expect to pay 700,000-900,000 VND for the driver to wait.
2. Round-trip with driver waiting: More convenient but more expensive. Good if you're visiting multiple caves in one day.​

Mini tip: If you're a group of 4-5, splitting the cost makes this cheaper than tour buses and more comfortable than motorbikes.

By Bicycle: (Not Recommended) 

Cost: Free (if hotel provides bikes) or 50,000 VND (~$2) per day

Duration: 60-90 minutes each way

Difficulty: High - long distance, hilly terrain, dangerous traffic on QL1A 

Only suitable for: Very fit cyclists who are comfortable riding in mixed traffic (cars, buses, trucks) and don't mind arriving hot and sweaty before doing physical activities.

Why I don't recommend it: The QL1A highway has fast-moving traffic, little to no shoulder for bikes, and the distance is tiring in Vietnam's heat. Most people I know who attempted this regret it halfway through.

Bottom line: Rent a motorbike for maximum flexibility and value, or join a tour if you want a guided, worry-free experience. Most travelers choose the motorbike option and love the freedom it provides.

Adventure Activities at Dark Cave (Complete Breakdown)

1. Ziplining Across Chay River (400 Meters - Longest in Vietnam)

Your adventure begins before you even reach the cave. After collecting your safety equipment (harness, helmet, headlamp) and signing a brief waiver (uh huh!), you'll climb up to the zipline platform overlooking the stunning Chay River. This isn't a gentle ride as it's a 400-meter flight that reaches speeds of 40-50 km/h as you soar over the water, jungle canopy, and limestone cliffs.

What it feels like: An incredible adrenaline rush combined with breathtaking views. You'll scream (everyone does), laugh, and probably want to do it again immediately. The landing is in shallow water, so you'll splash down and wade to shore.

Requirements:

• Minimum weight: 40 kg (88 lbs)
• Maximum weight: 90 kg (198 lbs) (RIP tall bodybuilders lol)
• Minimum height: 1.3 meters (4'3")
• Must be able to swim

Mini tip: Go early in the morning when there's no queue. During peak times (10 AM-1 PM), you might wait 20-30 minutes for your turn.

2. Kayaking on Chay River

After the zipline excitement, you'll hop into a kayak (single or double) and paddle approximately 500 meters along the Chay River to reach the cave entrance. The river is calm, clear, and surrounded by dramatic limestone karst mountains draped in jungle vegetation. It's a peaceful transition between the adrenaline of the zipline and the adventure ahead in the cave.

What to expect:

• Stable, beginner-friendly kayaks (no experience needed)
• Life jackets provided for everyone
• Takes about 10-15 minutes to reach the cave
• Crystal-clear water where you can see fish and rocks below

Photo opportunity: This is one of the most picturesque moments of the day. The emerald water, limestone cliffs, and lush greenery create stunning photos. Consider bringing a waterproof phone case or GoPro.

3. Swimming Through Dark Cave

Here's where Dark Cave lives up to its name. After docking your kayak at the cave entrance, you'll wade and swim approximately 400 meters into the cave using only your headlamp for light. The water depth varies from knee-deep to chest-deep (and occasionally deeper), and the temperature drops to a refreshing 18-20°C which is a total welcome relief from the heat outside.

What it's like:

• Complete darkness except for your headlamp
• Eerie silence broken only by dripping water and your group's voices
• Slippery rocks and uneven cave floor (water shoes essential)
• Stunning limestone formations. Stalactites hanging overhead, smooth cave walls worn by millions of years of water flow

Difficulty level: Moderate. You need to be a confident swimmer and comfortable in darkness. The cave floor is uneven, so watch your step. There are ropes along some sections to help you navigate.

Why it's special: Unlike Paradise Cave or Phong Nha Cave with their artificial lights and boardwalks, Dark Cave gives you an authentic explorer experience. You're actively navigating the environment, not just walking through a lit path.

4. Natural Mud Bath Experience

About 300-400 meters into the cave, you'll reach the highlight: a large chamber with a pool of thick, mineral rich mud. This isn't regular mud from what I know. It's therapeutic clay that's been forming for thousands of years, rich in minerals that are said to be good for your skin.

What you do:

1. Strip down to your swimsuit (this is required as no clothes are allowed in the mud)
2. Slather yourself head to toe in the thick gray mud
3. Float effortlessly in the mud pool (the density makes you incredibly buoyant)
4. Rinse off by swimming in the adjacent underground lake

What it feels like: Hilarious, bizarre, and surprisingly relaxing. The mud is thick like cake batter, and you can float without any effort. It's a uniquely fun experience that you'll be laughing about for days.

Important rules:

• No long sleeves or long pants allowed (mud gets trapped in fabric and is nearly impossible to remove)
• Women: one-piece or bikini swimsuit only, no cover-ups
• Men: swim trunks only
• These rules exist because too much mud was being carried out of the cave, affecting the ecosystem

Mini tip: The mud stains white clothing, so wear dark-colored swimwear you don't mind getting dirty.

5. Exploring the Cave in Complete Darkness

After the mud bath, you can venture deeper into the cave if you're feeling adventurous. Some sections extend another 200-300 meters with narrower passages, more dramatic formations, and even deeper darkness. This part is optional and depends on water levels and your group's comfort level.

What you'll see (with your headlamp):

• Massive stalactites and stalagmites formed over millions of years
• Cave pearls (rare limestone formations)
• Underground streams and pools
• Unique dark gray and black basalt rock (which gives the cave its name)

Swimming back: The return journey is the same route with swimming and wading back through the cave to your kayak and then paddling back across the Chay River to the main facility.

Optional: Water Obstacle Course & Swimming Area

Back at the main area, there's a floating water obstacle course (inflatable platforms, climbing walls, slides) that's included in your ticket. It's a fun way to cool off and play around after the cave exploration. There are also natural swimming areas in the Chay River where you can relax before changing and heading back.

Total experience time: 2.5 to 3 hours from zipline to finishing all activities.

What makes Dark Cave unique: It's the only cave in Vietnam that combines adventure sports (zipline, kayaking) with traditional cave exploration and a natural mud bath. You're not a passive tourist. You're an active participant in the experience.

How to Book Dark Cave Tour (3 Options)

Option 1: Go Independently (Cheapest & Most Flexible)

Total cost: 450,000 VND (~$19) entrance fee + transport

Best for: Budget travelers, experienced riders, those who want flexibility

How it works:

1. Rent a motorbike in Phong Nha town (100,000-150,000 VND/day)
2. Ride 16km north on QL1A highway to Dark Cave (15-20 minutes)
3. Buy your ticket at the entrance (cash only, VND preferred)
4. Do all activities at your own pace
5. Return whenever you're ready

Entrance fee includes: Zipline, cave exploration with headlamp, mud bath, kayaking, all safety equipment (helmet, life jacket), and locker use (50,000 VND refundable deposit).​

What you pay:

• Motorbike rental: 100,000-150,000 VND/day
• Gasoline: ~20,000 VND
• Dark Cave entrance: 450,000 VND (adult), 150,000 VND (child 1.0-1.3m)
• Food/drinks at the site: Optional (they have a small cafe)
  Total: ~570,000-620,000 VND (~$24-26)

Advantages:

• Cheapest option by far
• Complete flexibility over timing (arrive at 7:30 AM to avoid crowds)
• Can combine with other caves in one day
• Explore at your own pace without rushing 

Disadvantages:

• No guide (but the route is straightforward and staff are present)
• Must be comfortable riding a motorbike
• Need to arrange your own transport and navigate

How to rent a motorbike: Every hotel, hostel, and travel agency in Phong Nha town rents motorbikes. Compare prices and check the condition (brakes, lights, mirrors) before accepting. They'll hold your passport or a cash deposit.​

Mini tip: This is how most backpackers and independent travelers visit Dark Cave. The route is easy, the experience is the same whether you're on a tour or not, and you save 30-50% compared to organized tours.

Option 2: Book Through Your Hotel/Hostel in Phong Nha

Total cost: 500,000-700,000 VND (~$21-30) for full-day package

Best for: Travelers who want convenience without the hassle of planning

What's included:

• Round-trip transport from your accommodation
• English-speaking guide
• Dark Cave entrance fee and all equipment
• Lunch at a local restaurant (usually Vietnamese set menu)
• Sometimes combined with Phong Nha Cave or Paradise Cave

How it works:

1. Ask at your hotel/hostel reception about Dark Cave tours
2. Book the night before (or same morning if space available)
3. Minibus picks you up around 8:00-8:30 AM
4. Visit Dark Cave (2.5-3 hours)
5. Lunch stop
6. Optional: Visit second cave if booked
7. Return to accommodation around 4:00-5:00 PM

Advantages:

• No stress as everything is organized for you
• Meet other travelers (maybe save cost of exclusive cave tours like Hang En or Hang Pygmy when going as group by negotiating)
• Guide provides historical and geological context
• Hotel handles everything (transport, tickets, meals)

Disadvantages:

• More expensive than going independently
• Fixed schedule (less flexible)
• Group pace (may feel rushed or too slow depending on your group)
• Commission goes to hotel (that's why it's more expensive)

Popular tour options:

• Dark Cave only: 500,000-600,000 VND (~$21-25)
• Dark Cave + Phong Nha Cave: 650,000-750,000 VND (~$27-31)
• Dark Cave + Paradise Cave: 700,000-850,000 VND (~$30-36)

Mini tip: This is the best middle ground option for travelers who want some guidance and convenience but don't want to plan everything themselves.

Option 3: Book Online in Advance 

Total cost: 700,000-1,000,000 VND (~$30-42) depending on package

Best for: Travelers who want guaranteed availability and convenience from home

Platforms to use:

• GetYourGuide (most popular, good cancellation policies)
• Klook (competitive pricing, easy app interface)
• Viator (widest selection of combination tours)

What's included:

• Hotel pickup and drop-off (Dong Hoi or Phong Nha)
• Air-conditioned vehicle
• Professional English-speaking guide
• Dark Cave entrance fees and equipment
• Lunch
• Insurance
• Sometimes: Photography service, waterproof bags, extra activities

Advantages:

• Book from home before arriving in Vietnam
• Guaranteed spot (especially important during peak season)
• Professional, well reviewed guides
• Clear pricing and itinerary
• Easy cancellation policies (usually 24-48 hours notice)

Disadvantages:

• Most expensive option (30-50% markup over independent travel)
• Less flexibility with timing and pace
• May include stops at souvenir shops or restaurants with commission deals

When to book online:

• Peak season (May-August): Tours can fill up, especially weekends
• If you have limited time and want efficiency
• If you want to secure everything before arriving in Vietnam
• If you're not comfortable with last-minute planning

Mini tip: Online booking is convenient but expensive. If you have any flexibility just do the tour yourself without any guide.

Our recommendation:

For budget travelers and motorbike riders: Go independently (Option 1). It's cheaper, more flexible, and the experience is identical.

For travelers wanting convenience: Book through your hotel (Option 2). Good balance of price and service.

For travelers who want everything pre-planned: Book online (Option 3). Pay extra for peace of mind and guaranteed availability. Perfect for families with children.

What to Bring to Dark Cave (Essential Packing List)

MUST BRING (You'll be denied entry without these):

Swimwear - You MUST wear a swimsuit under your clothes. The cave won't let you enter without one. Buy at entrance for 100,000 VND if you forget.

Waterproof bag - For phone, wallet, keys. Everything will get soaked.

Change of clothes & towel - You'll be covered in mud and soaking wet.

HIGHLY RECOMMENDED:

• Water shoes or old sneakers (cave floor is sharp)
• Sunscreen & insect repellent (for before/after)
• Waterproof phone case (for photos during activities)
• Small dry bag for cash/valuables

DON'T BRING:

• Long pants or long-sleeved shirts (NOT allowed - mud removal policy)
• Expensive jewelry or watches
• Cotton clothing (stays wet forever)
• Flip-flops (dangerous in cave)

Mini tip: Wear a rash guard or athletic shirt you don't mind getting dirty. The mud stains, so don't wear white. duh!

Dark Cave vs Paradise Cave: Which Should You Visit?

Our recommendation: Visit BOTH if you have time. Do Dark Cave in the morning (8:00 AM) for adventure, then Paradise Cave in the afternoon for stunning formations. Many group tours combine both caves in one day or you can do these Phong Nha caves without a guide.

Frequently Asked Questions About Dark Cave

Q. How much does Dark Cave cost?
Full access is 450,000 VND ($19) for adults, 150,000 VND ($6) for children 1.0-1.3m tall. This includes zipline, mud bath, kayaking, cave exploration, and all equipment. The limited package without zipline/cave is 250,000 VND ($11).​

Q. What are Dark Cave opening hours?
Daily 7:30 AM - 4:00 PM (last entry 3:00 PM). The full experience takes 2.5-3 hours, so arrive before 1:00 PM. Best time is 8:00-9:00 AM to avoid crowds.​

Q. Can I visit Dark Cave independently without a tour?
Yes! Rent a motorbike in Phong Nha town (100,000-150,000 VND/day) and ride 16km north on QL1A highway (15-20 minutes). Buy tickets at the entrance. This is the cheapest option and gives you flexibility.​

Q. Is Dark Cave safe for non-swimmers?
You must be a confident swimmer as you'll swim across parts of the cave and through the Chay River. Life jackets are provided, but swimming ability is required. If you're not a strong swimmer, choose the limited package (no cave entry) or you can do easier cave tours like Phong Nha cave and Paradise cave.

Q. Can children visit Dark Cave?
Children over 1.3m tall (about 8-10 years old) and weighing 40+ kg can do the full experience including zipline. Children 1.0-1.3m can do kayaking and water activities but cannot enter the cave or zipline. Under 1.0m is free but very limited activities.​

Q. How long does the Dark Cave experience take?
2.5-3 hours total for the full experience: zipline (10 min), kayak to cave (15 min), cave exploration + mud bath (90 min), swim back + activities (30-45 min). Plan for 3-4 hours including changing and breaks.

Dark Cave is safe when you follow the rules, use common sense, and respect the environment. Thousands of people visit annually without incident. Be smart, be careful, and you'll have an amazing experience.