Ijen Volcano: A Midnight Trek to the Turquoise Crater

1 Chasing the Turquoise Crater: My Midnight Ascent of Ijen Volcano

I’ve always been spellbound by landscapes that challenge my understanding of nature—places where scientific facts and raw experiences fuse to create unforgettable memories. When I first watched a documentary about the sulfur miners of Ijen Volcano in Indonesia, I knew I had to stand at the crater’s edge one day. Stories of miners toiling in sulfur-laden air, the promise of turquoise waters in the caldera’s lake, and the legendary blue flames dancing in the night captured my imagination.

On a drizzly January night, armed with curiosity and excitement, I joined a midnight tour from the city of Banyuwangi in East Java. Over the course of several hours, I battled fatigue, the biting chill of high-altitude winds, and unpredictable rain to witness how science, human resilience, and nature’s wonder merge at Ijen’s volcanic landscape. I invite you to relive this journey with me, through all its challenges, mysteries, and splendor.

If volcanic expeditions fascinate you as much as they do me, you might also enjoy reading about my other memorable climbs: Mount Bromo in East Java, where I ventured into the heart of an otherworldly landscape; Mount Vesuvius in Italy, renowned for its explosive history; and Mauna Kea in Hawaii, an awe-inspiring mountain with a summit that often pierces the clouds.

2 Quick Facts About Ijen Volcano

Before we dive into the history, science, and eruptive events of the Ijen Volcano, here’s a quick overview of some essential facts about this iconic and active volcano:

• Location: East Java, Indonesia
• Type: Composite volcano (part of the Ijen Volcano Complex)
• Last Eruption: 1999 (monitored closely due to ongoing volcanic activity)
• Elevation: 2,799 metres (9,183 feet) above sea level
• Trek Duration: 1.5–2 hours (to reach the crater rim)
• Crater Lake pH: Approximately 0.2 (highly acidic)
• Temperature at the Rim: Can drop to ~10°C (50°F) before sunrise
• Key Attraction: Turquoise acid lake & elusive blue sulfur flames
• UNESCO Status: Included within the Ijen UNESCO Global Geopark for its outstanding volcanic landscapes and cultural significance.
• Local Workforce: Sulfur miners carrying up to 70–90 kg of sulfur per trip

3 Explore Ijen Volcano: Map of the Region

4 Midnight Departure: Into the Unknown

My adventure kicked off around midnight in Banyuwangi, the coastal city often considered the gateway to Ijen Volcano. Located at the eastern tip of Java—just a short ferry ride away from Bali—Banyuwangi doesn’t see as many tourists as more famous Indonesian destinations, but for me, that was part of its allure. It felt like an emerging frontier for anyone fascinated by volcanoes and off-the-beaten-path adventures.

I boarded a small tour van alongside fellow travelers—some were bleary-eyed from the late hour, others quietly excited about the prospect of an active volcano in the middle of the night. Our driver navigated through dark roads for about an hour before we arrived at Ijen’s basecamp. During the ride, I couldn’t help but recall the documentary about Ijen’s sulfur miners, who risk their health daily carrying heavy baskets of sulfur up the volcano with minimal protective gear. Now, that world was only a few kilometres away.

5 Ijen’s Volcanic Identity: A Brief Scientific Overview

Before I recount the actual trek, let’s look at the scientific charm of Mount Ijen:

• A Cluster of Volcanoes: Ijen is part of the Ijen Volcano Complex, a group of stratovolcanoes, calderas, and smaller cones in East Java. Frequent seismic activity, sulfur emissions, and occasional eruptions have molded its rugged landscape over time.
• UNESCO Global Geopark: Part of the Ijen Volcano Complex lies within a designated UNESCO Global Geopark, recognized for its exceptional geology and the rich cultural heritage surrounding sulfur mining.
• Turquoise Crater Lake:At the heart of Ijen’s main caldera lies a startling turquoise lake, widely reported to be one of the most acidic lakes on Earth. Its brilliant color arises from dissolved metals and volcanic gases—particularly sulfuric compounds—that react chemically under sunlight.
• Sulfur Mining: Sulfur vents around the lake deposit bright yellow sulfur along the caldera floor. Local miners manually harvest these deposits, carrying staggering loads on their shoulders. This is no modern industrial operation: the tools are basic, and protective gear is often minimal or nonexistent.
• Blue Flame Phenomenon: Ijen is famous for its blue flames, visible at night when sulfuric gases ignite upon contact with oxygen. The result is an ethereal glow that seems to dance on the rocks. The phenomenon is fleeting and conditions have to be just right for a clear view—sometimes it’s hidden by steam, rain, or shifts in volcanic activity.

With its mix of geologic oddities and extreme working conditions for local miners, Ijen offers a complex story that blends natural science with human endurance.

6 Gathering at Basecamp: Waiting in the Dark

We arrived at the basecamp shortly after 1:00 a.m. It was abuzz with quiet anticipation. Groups of hikers, some local and others international, lingered over steaming cups of coffee, bowls of instant noodles, or in my case, fried rice. Because it was January—well into the rainy season—conditions were unpredictable. A light drizzle would start, then stop, only to return a few minutes later. Temperatures hovered around 10°C (50°F) but felt colder in the damp, high-altitude air.

Our guide provided each of us with vital gear for the trek: a headlamp to see in the dark, an N95 mask for filtering sulfuric fumes, and a thin plastic raincoat in case the drizzle turned into a downpour. The damp chill made it clear that having a spare dry layer of clothing in my pack was a smart move.

By 2:00 a.m., it was time to begin. The guide called us together for a quick safety briefing, reminding us to stay alert on the slippery terrain and to use the gas mask if sulfur fumes intensified. With headlamps aglow, we set out into the inky darkness.

7 The Steep Hike to the Crater Rim

The initial trail to the crater rim gains hundreds of metres in elevation within a fairly short distance, making it a steep, demanding climb. Despite feeling well-rested at first, my excitement caused me to push the pace quickly, and my heart pounded from both the exertion and the thrill of heading into unknown volcanic territory. The path, though well-trodden, was covered in loose ash and small rocks, requiring a steady footing.

As the climb grew steeper, I occasionally glanced back to see a trail of headlamps zigzagging up the slope behind me—a mesmerizing, ghostly sight. The only sounds were the crunch of volcanic gravel underfoot, the wind whipping across the slopes, and the occasional chatter among hikers. The darkness magnified every sensation, and for a moment, I could almost forget the real reason I was here—searching for the blue flames and the sunrise.

After about an hour of strenuous hiking, I reached the caldera’s edge. In the pre-dawn gloom, I could make out wispy clouds drifting across the crater. Visibility was poor, and the famous blue flames were nowhere to be seen. Most hikers pressed on, descending into the caldera to try to catch a better glimpse, but the rest of us waited at the rim, hoping conditions might improve.

I had heard from the guide that a geologic shift occurred the previous summer, often causing the flames to be less visible or completely hidden. While it was disappointing to miss them, I knew the sunrise would bring its own spectacle, and I was determined to save my energy for that.

8 Waiting in the Cold: A Lesson in Patience

The next two hours felt surprisingly long. I found a small erosion channel in the caldera rim to shelter from the wind. By then, my clothes were damp with sweat from the hike, and the chill set in quickly. Changing into a dry t-shirt became a small lifesaver, providing immediate warmth. I could feel the temperature hovering around 10°C, though the wind made it feel even colder.

Occasionally, I peeked around to watch the steady stream of headlamps inching closer to the rim. Some trekkers from other groups stumbled back up from the crater floor, coughing from the sulfur fumes. Hearing their stories of limited or no visible blue flame, I made peace with the fact that I might not see the flickering lights I’d come to witness.

Still, I remained excited for the approaching sunrise. One of the joys of trekking up a volcano at night is that once daylight breaks, you’re treated to a dramatic reveal of the landscape you’ve been trudging through in darkness.

9 Sunrise Over Banyuwangi: The Grand Reveal

As dawn approached, the black sky took on a deep navy hue. Then, very slowly, it lightened to a soft gray, and I began to see the silhouette of the caldera wall and swirling tendrils of steam rising from vents below. Eventually, the first pale oranges and pinks glowed on the horizon, and my heart leaped at the sight.

All at once, the spectacle unfolded: the turquoise crater lake lay directly before me, shimmering like a giant jewel set into the volcano. Steam rose from the sulfur vents along its shore, occasionally catching the early light and forming ephemeral rainbows. On the other side of the rim, the sun broke over Banyuwangi, illuminating the rolling terrain and farmland below. For a few moments, I simply stood there, transfixed by the beauty and the interplay of colors—icy blues, fiery oranges, and every shade in between.

Knowing the lake’s acidity is extreme, I couldn’t help but marvel at how such a dangerous place could look so enchanting. It’s one of those experiences that reminds you of the Earth’s power: the same volcanic forces that create such striking visuals also harbor gases potent enough to make your eyes burn.

“The mesmerizing turquoise lake at dawn was worth every step of the midnight climb—and a vivid reminder of nature’s raw power.”

10 Venturing Into the Caldera: A Dance with Sulfur Fumes

Mesmerized as I was by the view from the rim, curiosity drove me to head into the caldera itself. To get closer to the crater lake and the sulfur vents, I had to carefully descend a steep, rocky path. The N95 mask I’d been given at basecamp became essential the minute I started down. Even with the mask, bursts of sulfur-laden steam scorched my throat and eyes whenever the wind changed direction.

Midway down, I noticed groups of exhausted trekkers heading back up, clearly worn out from the sulfur-filled air and the physically demanding climb. And then I saw them: the sulfur miners of Ijen, hauling basketloads of neon-yellow sulfur chunks. Their baskets, connected by a pole balanced across their shoulders, weighed anywhere from 70 to 90 kilograms. Yet there they were, ascending the same precarious path with hardly any protective gear. Some wore nothing more than a rag over their nose and mouth.

Seeing these miners in person made me realize that my own struggles—mild eye irritation, slightly labored breathing—were trivial compared to what they endured daily. It was humbling. It also crystallized the fact that Ijen isn’t just a geological marvel; it’s a workplace for people whose livelihoods hinge on harvesting this mineral resource.

Eventually, the sulfur fumes became overpowering for me. My eyes watered excessively, and my throat felt raw. Although I wanted a closer look at the vents, the discomfort quickly outweighed my curiosity. I turned around and began the grueling climb back to the crater rim, stopping frequently to catch my breath in the thinning air.

11 The Return Trek: A Changing Landscape in Daylight

Reaching the crater rim again felt like a small victory. The sun was now high enough to bathe the entire volcano in light. What had been a monochromatic blur during the ascent was suddenly a vibrant panorama of slopes, ridges, and clouds swirling against the blue sky.

The descent down the main path was surprisingly quick—about 30 minutes compared to the one-hour ascent in the dark. Daylight gave me the chance to take in details missed earlier: the lush green vegetation at lower elevations, the occasional wildflowers eking out an existence in the volcanic soil, and the fleeting glimpses of local wildlife.

By the time I returned to the basecamp, the air felt warmer, and I realized just how hungry I was. A hearty bowl of soto ayam (Indonesian chicken soup) and slices of fresh fruit provided the perfect post-hike reward. Between bites, I shared stories with other trekkers and they largely had about the same experience as me. But all of us agreed: the volcanic vistas at sunrise were astonishing enough to justify the night’s exertion.

12 Reflecting on Ijen’s Intrigue and Challenges

Back at my hotel in Banyuwangi, exhaustion finally caught up with me—I’d been awake for more than 24 hours, and the climb had taken a real toll on my body. Yet, despite crashing into bed almost immediately, I felt an overwhelming sense of happiness and gratitude for the adventure I had just experienced. Even though I missed the full display of the famous blue flames, I was thrilled to have witnessed the turquoise lake under the early morning light. As I drifted off to sleep, I couldn’t stop thinking about the awe-inspiring journey I’d just had and the renewed respect I felt for the sulfur miners, whose reality extends far beyond my own brief visit.

For me, Ijen is a place where science and humanity intersect—where tectonic forces create lethal gases and acidic waters, yet also yield commercial sulfur deposits. This natural laboratory is a stark reminder that Earth’s volatility can be both breathtakingly beautiful and incredibly harsh.

If you’re drawn to experiences that combine scientific wonder, raw natural beauty, and profound cultural encounters, Ijen is worth the climb. The trek itself might leave your legs shaky and your lungs working overtime, but once you witness the sun lighting up the caldera, you’ll understand why so many travelers count Ijen as a highlight of their Indonesian adventures.

13 Travel Tips

• Reaching Banyuwangi: If you’re visiting from Bali, take the ferry from Gilimanuk to Ketapang Ferry Port in Banyuwangi. From there, it’s an easy car or shuttle ride to most hotels or directly to the Ijen basecamp.
• Best Season to Visit: The dry season (May to September) generally offers clearer skies and less chance of rain, making for more reliable views and better hiking conditions. Visiting in the wet season (like January) can still be rewarding but be ready for rain and potential cloud cover.
• Accommodation: Banyuwangi has accommodations ranging from basic guesthouses to more upscale hotels. Staying overnight there allows you to rest up before the midnight departure to Ijen.
• Equipment and Clothing:
  • Dress in layers—the climb will make you sweat, but the summit can be quite chilly.
  • Pack a rain jacket and wear sturdy hiking boots with good traction, as the trail can be slippery, especially in the wet season.
  • Bring a spare t-shirt or two to change into if you get sweaty on the way up.
• Fitness Level: The hike is only a few kilometres but quite steep. It’s doable for anyone with moderate fitness, but expect to stop for breathers along the way.
• Local Guides: Hiring a guide is easy, especially if you book a sunrise tour. Many guides are ex-miners, offering invaluable local knowledge and insights into Ijen’s sulfur industry.
• Photography: If you want night shots—especially of the blue flames—bring a camera capable of long-exposure and a sturdy tripod. For sunrise, a wide-angle lens helps capture the sweeping vistas.
• Hydration and Snacks: Carry enough water and light snacks. You can buy some at basecamp, but it’s typically more expensive, and choices might be limited.
• Money Matters: Bring small Indonesian Rupiah bills if you plan to tip your guide or miners, buy coffee, or rent any additional gear at the basecamp.

14 Pro Travel Tips

• Check Volcanic Activity Reports: If the blue flame is at the top of your wish list, speak with local guides or check the latest volcanic activity updates. Sometimes vents shift or become obstructed, making the flames harder to see.
• Consider a “Taxi Service” on the Ascent: If you’re not confident in your hiking stamina, local entrepreneurs offer “trolleys” or “taxi services” to help you up. It can be pricey, but it’s an option if you have limited time or mobility.
• Protect Your Camera Gear: Volcanic ash, rain, and sulfur fumes can be tough on electronics. Wrap your camera in protective covers, and always wipe off any dust or ash immediately after use.
• Beyond Ijen—Additional East Java Adventures: Don’t overlook the rest of Banyuwangi and East Java. Baluran National Park (nicknamed “Africa in Java” for its savanna-like landscape) or Pulau Merah (Red Island) beach are excellent day-trip options if you’re looking to explore more of the region.
• Timing at the Crater: Plan when to descend into the caldera carefully. Going too early might leave you more exposed to thicker sulfur fumes in the dark. If you’re very keen on seeing the crater floor, balance your timing so that you’re not rushing back up just as the sun rises.

15 Closing Thoughts

Trekking Ijen Volcano was one of the most humbling and awe-inspiring journeys I’ve experienced. Even without the full dance of the blue flames, the sight of that vibrant turquoise lake at dawn was worth every drop of sweat and every moment of lost sleep. Watching the sulfur miners at work offered a profound look at the resilience of local communities who have adapted to these extreme conditions.

If you’re an experience-seeker with a thirst for scientific curiosity and breathtaking landscapes, Ijen delivers on all fronts. As you plan your own midnight ascent—headlamp on and gas mask at the ready—remember that the volcano’s mysteries are never guaranteed. But that, in itself, is part of the allure. You’re venturing into a place shaped by powerful natural forces, and all you can do is arrive prepared, stay safe, and embrace whatever wonders Ijen reveals.