Cave Adventures at Mulu National Park in Malaysia

Leaving Stone Horse Cave in Mulu National Park. Sometimes the best part of the cave trek for me was returning to the sunshine!

Mulu National Park in Malaysia is a wild and remote adventure wonderland with some of the biggest caves in the world, karst rock formations, tropical rain forest, and tons of creepy critters, especially bats. We had a blast hiking, climbing,  squeezing and swimming our way through the caves.

The park and town are only accessible by plane or boat, so services there are limited. I found it very challenging to find good information on the park so there’s a lot of planning pointers here. Jump around the post: Park Basics, Our Adventures, Cave Logistics, Other Logistics (Our map, plus budgeting, eating, and sleeping) and a few bonus pictures.

Heading into the park
The road to Mulu

Mulu Park Basics

Mulu is known for its caves so I didn’t expect to see so much wildlife just walking around the boardwalk paths. Our guides had great eyes and pointed out a few creatures we might have otherwise missed.

Spotted outside the park: One scorpion, two tree nymph butterflies, one stick bug doing yoga on our path, another stick bug with excellent camouflage, and one yellow snail.

And while the the creatures we found outside the caves were fun, the creatures we found inside the cave were even more interesting.  Mulu is home to over four million bats from 20 species. There is a great bat exhibit right near Deer Cave. Here’s a few fun facts about bats: some mother bats fly with babies that weigh up to a third of the mother’s weight. Bats are very beneficial since they eat lots of insects, like mosquitoes, and pollinate trees. The biggest bats at Mulu have wingspans of almost five feet. We didn’t see any that size, thank goodness. They can hang from the ceiling without exerting any energy because they have special tendons in their feet.

Spotted inside the cave: ccc
Spotted inside the caves: Some bats hanging from the roof, a baby bat hanging from the railing, lots of huntsman spiders, cave centipede, and thread worm string “webs”.

Aside from the bats, we saw other cave creatures like huntsmen spiders, some as big as my hands.  They are apparently “a little poisonous”. More interestingly, they don’t make webs and instead catch their prey by jumping. We kept an eye out for giant cave centipedes. The favorite group bug was the thread worms, who hang small strings from the cave ceiling to catch other small flying insects. Once the prey is stuck, the worms pull their lines back to the top of the cave.

If you really need more spiders in your life, try this cave or nighttime outside trick. Bring your flashlight up to eye level or shine your headlamp towards the rocks or trees, and look for little green glowing spots. Those are spider eyes.

Our Adventures

Unlike our usual solo adventures, we visited Mulu with our friends Mike and Jenny. These guys are the magic behind CrossFit Amatak in Phnom Pehn, Cambodia.

Waiting for the bats outside Deer Cave.
Waiting for the bats outside Deer Cave, which you can just see behind us.

Our first day, we hiked the boardwalk trail through the park to check out Deer Cave. Most nights, you can see millions of bats leave the cave. They fly out in large groups to protect themselves from hawks or snakes.

The night we watched, the bats streamed out together in about a dozen groups of undulating columns that looked like snakes in the sky. Some nights if the weather is bad, they stay in, so we were warned to look for them early in the trip. Other nights, they fly out in one giant hoard.

If you squint a little you can see the horse head.
If you squint a little you can see the horse head.

Our first real caving adventure was through Stone Horse, which you probably won’t be surprised to hear is named for a rock that looks like a horse. This was classified as “moderately” difficult. There were a few spots where we climbed up, down, over and through different rocks formations, but the toughest challenge was keeping our footing on the slippery mud floor. We did have a few traverses where we clipped into the rope, but they were pretty easy to navigate.

Throughout Stone Horse, we passed lots of chambers that were full of bats. Most were hanging out, maybe sleeping, but some chirped and squeaked at us and even took a few quick aerial laps around the cave (they echolocate outside of human hearing but communicate to each other in chirps and squeaks). I do not think they enjoyed our lights in their eyes.


Going down!

Next up on Day 2 was Racer cave. We harnessed up for this trek as well, and it had more ups and downs rather that just heading across things. It’s named for Racer snakes. This was also our “test” day in which the guides would decide if we were good enough to trek the advance-level Clearwater Connection cave. (Spoiler alert: we passed.)

I thought Racer was a lot more fun and active than Stone Horse and would recommend it if you only have time for one cave. We also took a long boat to get there instead of hiking through the park on the boardwalk which was a nice way to see more of the park.

Squeezing through!
Squeezing through!

Our third day of caving was on the Clearwater Connection Route. This is an advanced route because it has some extremely tight squeezes, and the total time in the cave is about 5-6 hours. I really appreciated that  the route was not an out and back one, instead, you go through one cave, squeeze through into another cave, and then hike and swim out from there.

It would be fair to note that while spelunking is an exciting activity, based on our earlier adventures and my prior experience in a lava tubes in Washington, I have come to the realization that I am more of an outdoor adventure girl. The Clearwater Connection was likely my final cave adventure. There were three different squeezes that I found incredibly challenging and uncomfortable. In each of these spots, we had to wriggle and twist our way down through small holes. Complicating the matter, a lot of the rocks were wet and slippery and we were sweaty, so grips were tough, and vision was tough too because in order to see your hand and footholds, you had to be able to aim your headlamp at them.

I was definitely the most uncomfortable out of our group, but everyone was really supportive, especially our rear-guide, Joe, who spent most of the tour joking about getting lost behind us.

Here's Adam trying to figure out how to fit through one of the squeezes.
Here’s Adam trying to figure out how to fit both his legs and his upper body through one of the squeezes.

Fortunately, after being completely mentally exhausted, hot and sweaty, we ended up at the best part of the tour: the Clearwater River. Here, we waded and swam through a perfectly clear river that flowed through the cave. We even had a chance to try one armed swimming to keep some of our electronic possessions out of the water in the deep spots.

The best part!
The best part!

In addition to the caves, we had a chance to check out the rain forest, both on the ground and via a canopy walk through the treetops. I’d heard we might see monkeys on the walk, but if they were nearby we did not spot them. Even without the monkeys, I enjoyed walking along the swinging rope bridges and learning a bit more about the forest from some of the exhibits posted along the way. For instance, we learned about dipterocarps, the cicadas of the tree world. Once every five to ten years, all the dipterocarps in an area flower at once, and then disperse seeds via helicopter leaves a few months later.


Our final adventure in the park was a trek through Deer Cave, which we’d previously only seen from the outside, then up and down some jungle mountains to the Garden of Eden, to a swimming hole with a big waterfall. We not only waded up an outside river, but we also got to wade and swim through a cave river. Sometime during the trip, I caught my first leech with my femoral artery and proceeded to do a very intricate jumping and shrieking celebration dance. I’m sure it was exciting for everyone to watch.

Wading to the Garden of Eden
Wading to the Garden of Eden

Aside from activities in the park, there wasn’t a lot to do in Mulu. We spent some time playing board games and reading, and found that the best beer drinking spot was the bridge to the Marriott where we could watch the Mulu crew team train every day in the evening.

There they go!
There they go!

Logistics – Cave Guides, Eating, Sleeping & Budgeting

Don't get me wrong, there's lots of spots where you NEED a guide.
Don’t get me wrong, there’s lots of spots where you NEED a guide.

One thing to note about Mulu is that you are required to have a guide if you’re venturing into most of the caves or on some of the longer hikes. The number of people who can do each trip is also limited. We had no issues signing up about a month early but the park recommends planning adventures well in advance.

Caving adventures are divided into show caves, intermediate caves and advanced caves. Show caves are open to everyone and have boardwalk paths with lighting. Intermediate trips are guided but open to anyone willing to sign up. To participate in an advanced trip, you need to have written proof of your caving experience or get a guide’s approval after completing two intermediate trips.

Once you arrive, the guides provide you with helmets, lights, and harnesses. The only things we needed to bring were lunch for the long hike, plus cameras and water. It’s best to have a backpack or shoulder bag to keep your hands free for scrambling and climbing. I was surprised how hot and sweaty we were in the caves, so I was happy to have a dry sack for my camera, even before we hit the parts in the river. If you happen to have a longer pair of shorts, I would recommend those as well to wear under the harness.

Other Logistics – Sleeping, Eating, and Budgeting

Here’s a map with most of the spots in town one might visit:

Pro Tip: Cover your caving light for better pictures.
Pro Tip: Cover your caving light for better pictures.
  • There is limited accommodation inside the park, but we found a great place outside the park called Mulu Village which I would highly recommend.
  • We struggled to figure out how much cash to bring. There are no ATMs anywhere.
    • However, you could pay for your guided park events with a credit card and 2% surcharge, and also get 50 – 100 extra ringgits as a cash advance
    • During our 5 day trip we spent:
      • 490 ringgit on our accommodations
      • 1500 ringgit on tours, including the entrance fee, 3 days of caving, one guided trek to the Garden of Eden and the canopy tour
      • 1000 ringgit on food and drinks. We ate at the park, and at Stella Cafe across from the hostel, splurged one night for dinner at the Marriott, and drank a lot of Tiger beers which we could buy for 6-10 ringgit a pop around the town.
      • When we were there ringgits were about 4 to the dollar.

Bonus Pics


8 thoughts on “Cave Adventures at Mulu National Park in Malaysia”

  1. dear Lesie and Adam,

    we follow you every where.
    in most coutries we also have been.
    not with all your adventures, but still.
    do you go to Indonesia?
    we go tomorrow for one month to Bali.
    a very nice island with very friendly people.
    if you are around, please visit us.
    we wish you a fine and save further trip.
    uncle Wim and aunt Nel

    1. Hello! Thank you so much for following. We don’t have plans for Bali yet but we’ll email you and see if we can figure some out.

  2. Leslie:
    Thank you for these marvelous posts. This one is particularly interesting. I imagine you typing away on a small laptop or even your phone, at night in the pouring rain, in a thatched hut, chasing away the flying and biting creatures, drinking an exotic beer now warm, trying to keep your devices dry and charged. The photographs are great. The one of you and Adam in the beam of light in the cave is somehow hilarious and spiritual at the same time.

    1. Hi John, thanks so much for the comment and support. You’re giving me too much credit. I usually only have one or two of those challenges at the same time, rather than all at once. And the exotic beer is almost always a local domestic choice, so while they have local names like Bia Hanoi, Ankor or Tiger, they’re all pretty similar and best drunk before they get warm.

  3. Love following you, my dears.
    It is intetesting to imagine you sitting on a rock and writing, as you swat away giant slug-type night creatures.

    Love Love and More Love, to the caves and back!

    1. Hi Auntie Gail! Thank you so much. In a big culture mash up, we’re going to Phnom Penh’s Octoberfest tonight, so I will probably do a little celebrating there. Love you!

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