Indonesia (Republic of Indonesia)

Languages: Indonesian

Currencies: IDR · Indonesian rupiah (Rp)

Capitol: Jakarta

Continents: Asia

Borders: Malaysia, Papua New Guinea, Timor-Leste

More useful information

Area: 1,904,569km2

Population: 273,523,621

Traffic/driving side: left

Landlocked country: No

Independent country: Yes

United Nations member: Yes

IDD Prefix: +62

Timezones: UTC+07:00, UTC+08:00, UTC+09:00

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Last updated on July 10, 2024
Kawah Ijen Crater in Indonesia

Hiking Mount Ijen in East Java in Indonesia is a truly magic experience! Trekking through Java island was one of the most stunning adventures I have experienced in my life. It’s a unique mixture of natural wonders with cultural heartland. I started my trip in Jakarta (crazy city!), stopping in Yogyakarta – famous for its rich traditional arts and cultural performances, and incredible Borobudur temple complex, to reach Mount Penanjakan – the best sunset spot, Bromo Tengger Semeru National Park and Kawah Ijen. Then I continued my adventure through Bali, Flores and the exotic islands: Rinca & Komodo Islands, and Kanawa Island – heaven on earth!! 

Ijen Volcano adventure is magnificent – Mount Ijen is the world’s largest acidic volcano with stunning turquoise crater lake boiling at 300 degrees! Additionally, you can witness the famous Blue Flames – a phenomenon out of this world. 

Hiking Mount Ijen - the world’s largest acidic volcano!

Hiking Mount Ijen is quite challenging, however it is accessible to every traveler and does not require a special fitness level. Although you need to know it is still a few hours night trek through a rocky terrain. We didn’t have any guide but most people would be hiring one. Check Mount Ijen Crater Tour from Bali.

Hiking Ijen Crater lake

How long does it take hiking Mount Ijen?

Most visitors would book a tour to Ijen Crater but it is also doable alone, as the path is pretty maintained. The road is quite simple, you will walk few kilometers to get to the top of the crater. Start trekking toward Ijen crater early enough (we started at 1a.m.) to witness the sunrise and blue flames around 4am. You can’t miss either of it! Only if you’re there before 4 a.m. you might have a chance to see a unique phenomenon in the bottom of the crater – the blue flames. Ijen Crater hike is about 9 kilometers both ways.

Magnificent phenomenon of the blue flames in Kawah Ijen.

The blue flames you see at the Ijen Crater in Indonesia are caused by ignited sulfuric gases that emerge from cracks in the volcano at high temperatures. The gases burn with a blue hue when they come into contact with oxygen at temperatures exceeding 360°C (680°F)! 

This phenomenon creates a spectacular and unique sight, especially in the dark of the night. The combination of the blue flames against the dark volcanic landscape makes for a truly unforgettable experience. However, it’s important to note that witnessing the blue flames can be physically challenging due to the steep terrain, the toxic gases present in the area and the heat! Some habitats say that Ijen blue flames can only be seen once a week but I’m not sure if it’s true.  

Ijen Crater acidic lake.

While it is slowly getting bright, the day uncovers the beauty of the acidic lake. Ijen volcano contains the world’s largest acidic volcanic lake. The acidic lake has a green-blue lagoon color and boils constantly at 300 Celsius degrees!

In the bottom of the crater local miners are digging sulphur from the active vents at Ijen. The whole area is covered with a smoke coming out form the underground, as the liquid red sulphur erupts from the vents and in contact with air cools to a yellow color. The choking smoke is terribke so you better wear a mask, otherwise it would be difficult to breathe properly. 

Sulphur mining at Ijen Crater.

Kawah Ijen sulfur miners extract sulfur from the volcanic crater. These miners endure challenging working conditions, including toxic sulfur gases, rugged terrain, and heavy loads, to extract sulfur from the volcanic vents within the crater.
Can you believe the miners typically carry large baskets of sulfur, weighing up to 70-90 kilograms, from the crater floor to the processing area outside the crater rim, often enduring harsh fumes and difficult physical labor in the process.

Their work is not only physically demanding but also carries health risks due to prolonged exposure to sulfur dioxide gas, which can lead to respiratory issues and other health problems. Despite the challenges, the sulfur miners at Ijen Crater continue their work as it is a vital source of income for the local communities in the area. Efforts have been made to improve safety conditions and provide protective gear for these miners but you can also contribute by small tipping. They are extremely nice, shy and friendly. Some of them will uncover parts of their bodies showing shoulders and back deformations. Some will let you try to carry the basket hahhhha! Their bones are covered with a crust skin from the stick holding heavy baskets. 

From the top of the caldera they still need to walk 3 km to reach the payment spot, where the stones are stored. The minors are so tiny that it’s actually hard to believe that they can be so resistant.

You can also take a walk around the caldera to admire the lake from the top perspective.

Safety advise for hiking Ijen Crater.

Safety: As this is an area of high volcanic activity – so it is dangerous and you enter on your own responsibility. Besides you are constantly in the clouds of sulphur smoke – and this gas is toxic, so consider having a gas mask if a simple face mask is not enough for you. For me it was manageable with a simple face mask. 

Is hiking Mount Ijen safe and how to prepare?

Level of difficulty: The hike to the crater rim and down to the blue flames can be physically demanding, especially the ascent back up due to steep and rocky terrain. The trek usually starts in the early hours of the morning (we started at 1am) to reach the crater rim before sunrise, to witness the surreal blue flames and the acidic crater lake. It takes approx. 3 hours to reach the crate and it’s an optimal time to admire the blue flames.

The length – You’ll be hiking down through the rocky terrain to the bottom of the crater lake. This is where you meet the minors (always let them go first!). You probably won’t stay too long at the bottom of the crater, because of the choking smoke. It’s also possible to walk around the crater. If you prefer to go with a tour to get more advice and some guidance on the way, there are few popular options. 

Ijen Crater is easily accessible from Bali, there’s one popular tour on Klook – Ijen Blue Fire Hiking Tour from Bali.

What to wear hiking Mount Ijen?

WHAT TO WEAR: Wear layers as it can get cold on the crater rim. Sturdy hiking boots with good grip are essential. Face/gas mask, plenty of water and some snacks /chocolate, nuts, protein bar/. Headlamp – Since the hike starts in the dark, a reliable headlamp is a must.

BEST PLACE TO STAY WHEN HIKING MOUNT IJEN: The best place to stay in a village called Banyuwangi. There ‘s lots of accommodation options. Amazing budget stays start from few dollars per night on

Exceptional hotels (4* and 4.5*) and B&B stays start from only 30$ on

IJEN CRATER ENTRANCE FEE: 100.000 IDR (~6 USD) on weekdays and 150.000 IDR (~10 USD) on weekends. 

GUIDE: A guide is not required, unless this isn’t your first volcano or night hike!

Explore Mount Bromo and Mount Penanjakan tours.

There are many tour options to see wonders of Tengger Semeru National Park. Some most popular options, including multiday immpressive advantures, with best reviews contain:

Best hikes in java, Indonesia

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Sassari Sardinia

Hey - I'm Eva!

Hiker, adventurous traveler and the author of this blog. My biggest joy is mountaineering and writing reportage travel stories here on this blog, to help you create a unique travel experience. Traveling is freedom, allows you seeing the world truly, meet communities, grow. Taste it!

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