When a former coworker told me she trekked through the largest cave in the world I couldn’t ignore it. You have to sign up about a year ahead of time and when I looked it up, it was sold out. I signed up to be alerted about it next year and I was surprised when I received an email last July saying they were adding an additional sign up period in November. I immediately started emailing all of my friends for partners in crime on this adventure. I found two friends and the minute the registration opened we signed up to go in May.

SEE ALSO: Frequently Asked Questions About my Trip to Son Doong Cave

About Hang Son Doong

Hang (meaning Cave in Vietnamese) Son Doong is the largest cave in the world and located in Central Vietnam in the Quin Lorem province. Discovered by a local, Mr. Ho Khanh in 1990 on accident it was forgotten until 2009 when Mr. Khanh brought British cave explorers Deb & Howerd Limbert to explore the surrounding area’s caves and eventually explore Hang Son Doong.

The tour is four nights and five days long inside the park and caves with Oxalis Adventures Tours plus a night before and after the trip outside the park. They are the only tour company that is allowed inside Hang Son Doong to run tours. They run around 700 people in a year, in groups of ten, non stop during the dry season.

The Largest Cave in the World – Hang Son Doong, Vietnam
Phong Nha

Phong Nha Town

My friends had never been to Vietnam before so we spent the week beforehand in Hoi An and Hue, Vietnam on the way to Phong Nha. We arranged a car service from Hue to where we were staying in Phong Nha with Oxalis. Some of the group stayed in the Oxalis Home Office but there is limited room and we stayed down the street at Ho Khanh’s Farmstay.

Phong Nha is already a popular destinations for travelers, not just for Hang Son Doong. There are several other adventure expeditions around the area in the National Park. The “town” is a single main street with restaurants, tour agencies and small shops. Farther down the river away from the main street shops are where most of the places to stay are located. We borrowed bikes (there are no taxis) from our hotel and went to town for some supplies and food. Make sure you bring everything you need before you get to town, there are very limited options to buy supplies.

That evening we were picked up by Oxalis and we went to their homestay. We had a presentation about the tour, what to expect, what to bring and some general safety guidelines. We got our helmets and had dinner with the group.

Accompanying our group of 11 (we had one extra) would be six guides, 20 porters, two cooks, two park rangers (required by the park) and one of the early explorers of the cave Deb. In addition to the office staff they also employ a staff of women who did all the washing and preparing of our camp gear (tents, sleeping bags, etc).

DAY 1 – Hang En

It was only the beginning of May and it was already extremely hot and humid in Phong Nha. The first day we would spent a good portion of the day outside so we left early hoping to avoid a little bit of the heat. We took a ~30 minute mini bus ride into the center of the Park and stopped to look over the Ho Chi Minh Trail.

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography

We started the tour with a downhill hike through the jungle for a little bit before coming into the flat of the park. We stopped for lunch in the minority village of Ban Doong along the way, the only group of people living inside of the park. Oxalis has helped the village raise money, building a school and supporting them, especially during the rainy season when often their entire village is washed away.

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography

After lunch we were lucky and it decided to rain so it kept us cool while we hiked to the entrance of Hang En. The water wasn’t too deep yet and it was fun wading through the streams and avoiding leeches along the way.

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography

As we entered Hang En we used our headlamps and helmets for the first time. The guides gave us battery packs for our lights (it definitely added a neck workout, they were heavy!) and we started climbing into the cave through the boulders.

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography

After our first bit of trekking in total darkness we came out on top of the boulders. We got our first view of the camp in Hang En from up above with the doline light shining in. We then climbed down and crossed the water via bridge. There were so many birds inside this cave! We learned that the “sand” we were walking on was really formed from all the bird poop falling. We camped in Hang En on our first and our last night of the trip. If you’re looking for a shorter trip, you can sign up and do Hang En just as an overnight expedition if you want.

DOLINE: The openings in the cave that allowed light to shine inside the caves from above.

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography

That night we lit our tents with our mini headlights and we climbed up to the other side of the cave for photos looking down on camp. There were multiple stops where the guides would “light paint” for us so we could take some pretty cool long exposure shots.

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography

DAY 2 & 3 – Inside Son Doong

The Largest Cave in the World – Hang Son Doong, Vietnam
Exiting Hang En – Ronald Fritz Photography

The next morning we left to start trekking through and out of Hang En on the other side to make our way to Son Doong. After leaving Hang En we hiked through the jungle for a little bit before starting a long hike uphill (not the longest one of the trip though!). We had lunch before heading to the entrance of the cave where we would repel down with harnesses and the help of the guides. Going down was much harder than climbing back up! This was also the one time I took a major spill landing abruptly on my butt on the rocks. I was fine though, just a few bruises. We had harnesses but the porters all zipped down and back up later without any help!

We would then spend the next two days hiking into Son Doong staying at two camps inside the cave. Camp 2 and Camp 3. Along the way we had plenty of time to stop for photos and the guides and crew helped us create long exposure shorts or stand in as models for scale.

Largest Cave in the World Hang Son Doong Vietnam
Garden of Edam
The Largest Cave in the World – Hang Son Doong, Vietnam
Doline 1 – Ronald Fritz Photography
The Largest Cave in the World – Hang Son Doong, Vietnam
“Hand of Dog” Ronald Fritz Photography

We passed by some pretty amazing fossils, formations, stalactites and stalagmites, found some new species inside the cave, and saw Son Doong’s famous “cave pearls”. Depending on the time of year the water levels rise and fall so you may be walking along water or you may be higher up on the rocks. One of the most amazing things hiking through the cave was the different terrain and surfaces we passed across.

There was a whole section where the rock look slick but it wasn’t slippery at all and felt like rubber on our shoes. There were also times when we were walking on sand like ground but most of the time we were climbing over the boulders inside the cave.

One of the last activities we did inside the cave was take a paddle boat to see the “Great Wall of Vietnam”. The water was high while we were there so we took a paddle boat. Next year the tour will end scaling up the wall and exiting through the doline at the top of the wall, eliminating a day of the trip so you can go straight through and not have to go in and then back out the same way.

The Largest Cave in the World – Hang Son Doong, Vietnam

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography
The Largest Cave in the World – Hang Son Doong, Vietnam
“Cave Pearls” and an undiscovered species
The Largest Cave in the World – Hang Son Doong, Vietnam
“Camp 2” Ronald Fritz Photography

The Largest Cave in the World – Hang Son Doong, Vietnam

The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography
The Largest Cave in the World – Hang Son Doong, Vietnam
Stalagmites and Stalactites
The Largest Cave in the World – Hang Son Doong, Vietnam
Ronald Fritz Photography
The Largest Cave in the World – Hang Son Doong, Vietnam
Camp 3 – Looking down at camp and up from the camp the other direction

DAY 4 – Hiking out Son Doong

Because we couldn’t hike completely through the cave like you will in the future, Day 4 for us was hiking back the way we came in covering the ground we made on Days 2 and 3. It was much faster and much easier that day. We flew through. We stopped for lunch at Camp 2 before heading back and spending the fourth night back at Camp 1 in Hang En. Although the tour doesn’t have this additional day anymore I loved being able to walk back and see one of the best sites of the cave the Garden of Edam again on the way out.

The Largest Cave in the World – Hang Son Doong, Vietnam
Our group and guides at Camp 3

DAY 5 – Hiking back out of the park

While the last day of hiking wasn’t the most challenging but it was the most physically taxing. We took a different route out then we did on the way in when we stopped at the village. After hiking out of the cave and through the park the last part to hike to the road where we were picked up was an hour and half hike uphill. My legs were burning. One of the guides took pity on me and gave me his homemade leaf fan.

The Largest Cave in the World – Hang Son Doong, Vietnam
The final view from inside the cave before leaving Hang En – Ronald Fritz Photography

At the top I was so glad to have a cold drink waiting. We separated from the guides and the rest of the porter team and our van picked us up and brought us to Chay Lap Farmstay, where we stayed on the last night. The pool, laundry and cocktails were an amazing end to the trip.

The Largest Cave in the World – Hang Son Doong, Vietnam
Chay Lap Farmstay

Conservation of Hang Son Doong

The trip is pretty pricey, a little more than $3,000 when it is converted from VND to USD with about $660 of the cost going towards the park entry fee and to the park system.

Hang Son Doong is a recent discovery and has been recognized as an opportunity to make significant money for the area. Because of the high cost and the physical difficulty to get inside the cave it limits the number of people able to visit (and thus collect park fees from) each year (although that number is growing quickly).

There is a proposal to build a cable car through the park and into parts of the cave, something that would cause significant damage to the natural structure of the cave, having to blast areas of it away to make room and build structures.

There are several groups and people bringing awareness to this issue and putting pressure on the Vietnamese government to put a stop to the destruction of the cave by building this cable car system. At this time the project seems to still be up for debate while plans are being drawn. It is not confirmed that it will move forward or that it will be stopped. I urge you to do your own research and bring as much awareness to the cause as possible in whatever way you can.

SEE ALSO: Frequently Asked Questions About my Trip to Son Doong Cave

Thanks to Ronald Fritz Photography for sharing your photos. And check out this video our cave mates from We won’t be right back made of our trip below.