An Eerie Beauty: Batur

Lake Batur
May 19-21st 2015

Diving in Bali usually conjures up images of Molas and Mantas over rich reefs in clear, warm, tropical waters. But high up in the volcanic North of Bali is a large lake offering those curious enough the opportunity to dive somewhere completely different. The low visibility created an eerie yet beautiful experience as we dived past imposing granite cliffs and found large lava fields, all inhabited by small crabs and fish. Descending to the depths of the lake was like entering a lifeless alien world that spoke volumes about the impact humans are having on the planet. An exploration trip to dive at altitude in a body of water no‐one has ventured before requires careful planning. With the right training and preparation, the results were immensely rewarding.

Lake Batur


Lake Batur is a crescent shaped lake lying within the heart of a huge crater created when the original Mount Batur violently erupted 20,000 years ago. Within this crater, the new Mount Batur has been slowly rising up and has erupted multiple times in living memory. The volcano draws thousands of tourists every year to hike up to the crater’s edge to watch the sun rise over Bali.

Situated high up in the mountains, the water level of the lake has been rising over the years. The jetty used by the local villagers is now underwater and no‐one knows why the water level is rising so quickly. The lake is not known as a dive destination, and has only been dived by Leon Boey and Terence Lee in 2014.


With the right training and a strong team, it’s possible to dive pretty much anywhere there’s water deep enough. In August 2014, Leon thought it would be interesting to see what diving in the lake would be like. Together with Terence, they filmed what volcanologists believed to be the first evidence of pillow lava in Indonesia. Pillow lava is formed by the extrusion of the lava under water. To be able to prove this required a sample of the lava, so a return trip to the lake was planned.

While planning our dives, we also wondered what the bottom of the lake was actually like; would there be life down there; how deep was it; what is the bottom made up of? So many questions unanswered, and as far as we know, we would be the first people on the planet to see the bottom of Lake Batur. There are not many places on the planet that man hasn’t been, so to be able to say we would be the first was tremendously exciting.

people leon and tanks

Kids and tanks

The logistics of remote diving

The bottom of the lake was reported to be in the 60m range, and therefore required the use of mixed gas to be able to be dived safely. The pillow lava was found at recreational depths, and large amounts of equipment would be needed to bring the samples back to the surface. With no diving facilities around the lake, we needed to bring everything up to the lake with us.

Using Living Seas Bali in Sanur as a logistics base, it was a steep 2 hour drive through the stunning Balinese countryside to the top of the crater’s edge 1300m above sea level. The crater’s edge down to the lake was a windy drive down to 1000m. With minimal space for equipment and multiple tanks, we drove up to the lake each day, with additional planning required due to the changes in altitude involved.

Batur Sunset

This particular expedition was planned to coincide with a group of students from the Nanyang Technological University in Singapore, who were in Bali to study the volcano. We were invited to give a talk at the end of each day of diving, to share our experiences and what we had learnt from diving the lake. They also brought equipment to examine any samples that we would bring up.

Leon Batur Balcony

In May, the weather in Bali is gloriously sunny, but there was a noticeable drop in temperature as we climbed from sea level to the lake. From Leon’s previous trip, we knew that despite the sunny conditions, the water would be cold and that drysuits were required to stay warm during our dives. The thick undergarments also helped protect us from the strong winds on the lake.

The wind made the surface a little choppy and with no dive boats available, we would be diving from a fishing boat, making entry and exits harder than usual. In addition to our regular diving gear, we carried bright HID canister lights, sample bottles and an axe to collect samples of the lava. Unsure of how the underwater camera casing would cope at depths whilst at altitude we didn’t bring them deeper than 30m.

batur scuba

Diving into the unknown   

Overall, the diving was eerie and a little spooky, yet spectacular and highly rewarding. A thick algae bloom in the top few meters of water reduced visibility to such an extent that touch contact was needed to ensure we were not separated. Once we were deeper than 10m, the visibility improved and we could see what the sides and bottom of the lake were like. The volcanic ash formed a gelatinous coating that wobbled if you disturbed it. Through this thick layer emerged the pillow lava and imposing granite cliffs, bathed in a warm orange glow as the sun tried to penetrate the water.

algae rock batur

We stumbled upon a perfectly preserved tree, which must have fallen years before from the steep sides of the crater above. The twisted root system created a ghostly work of art that emerged out of the gloom. There were thousands of shells scattered on the lake bottom, potential victims of the rising water level. Despite the gloom, there was an abundance of life in the shallow water. Crabs and shrimp were seen scuttling across the rocks with the occasional fish swimming around.

bottom lake batur

On our first day diving, we retrieved a sample of the pillow lava for the students, using an axe and brute force. This took some effort, as working underwater isn’t the easiest thing, having to worry about buoyancy and position, whilst making sure you get your objective completed.

On the second day, we planned to hit the bottom of the lake, somewhere we know nobody has ever seen before. Descending down a steep slope, it didn’t take us long to reach 60m. The bottom of the lake was like something from an alien world. The thick gelatinous layer of volcanic ash spread out in a perfectly flat and undisturbed layer.

What was astounding though, was that every metre or so, punctuating the silky layer of silt, and spread out for as far as we swam, was trash. Plastic bags, water bottles, paper wrappers, foam cups, they were everywhere. Imagine finally visiting Mars, only to find a large rubbish dump there.

Considering the depth of the sediment was longer than Leon’s arm, we can only speculate on what other heavier items must have passed through the top layer of sediment to rest on the volcanic rock below. We were not expecting this, and this experience really highlighted the impact humans can have on really remote places. Unseen and unknown, where else in nature are we having such an irreversible impact?

Sharing the Passion

Later that evening, Leon gave an impassioned talk to the NTU students about our experience in the lake. He talked about the necessary curiosity that all students of Mother Earth have to embody, and why we wanted to dive in the lake in the first place. Sharing what we had discovered about the bottom of the lake, the audience was noticeably taken aback by the extent of the trash we had seen littering the untouched bottom of the lake.


The students then examined our rock samples with a microscope and confirmed that it was in fact volcanic in nature. They mused about the origins of some of the plate like deposits we had shown pictures of, and suggested they could have been a weathering layer from previous eons when the rock was exposed to the air.

batur lava samples

While planning for these dives, we heard stories from the locals that the water level has been rising continuously for a long time. The beach that Leon and Terence used to enter the water in last year’s expedition is currently under water. Could the heavy sedimentation be the cause of the water level rising? Our dives have opened up many more questions we are looking to answer.

The Spirit of Exploration

Exploration is all about the unknown, to see what you can achieve. This time we experienced something unique and we can’t wait to see what other secrets the lake reveals.

We really were true explorers for a few days, and that makes you feel pretty amazing.