Ijen Crater


Ijen Crater: A small but magical caldera

Mountain Stats
Natural Form and History
Climbing Experience & Itinerary
Support Facilities
Safety & Accessibility
Special Tips
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Quick Answers

Q:How do you climb the Ijen Crater?
A:Climbing Ijen Crater will take about 2 hours. If you manage to get to the caldera lake before sunrise you’ll be able to see the magical blue fire in the dark, a truly unique experience only available at Ijen Crater and in Iceland. A permit is needed for this climb and the ideal time to embark on your journey is 1 am.
Q:What is the "Blue Fire" of the Ijen Crater?
A:The blue fire is ignited sulphuric gas emerging from under the ground at temperatures up to 600 °C (1,112 °F) in the Ijen Crater. The flames have been known to rise up to 5m (16ft) high, but usually hug the ground. They are usually only visible at night time. It is the largest blue flame phenomenon seen in the world, with the next location to see it being in Iceland.

Climbing Ijen Crater Indonesia - Mountain Stats

2,350m (7,710 ft) (at the crater rim)
Climbing Height
Less than 500m
  • #1 Largest Blue Fire Phenomenon On Earth
Other names
  • Kawah Idjen

Climbing Ijen Crater Indonesia - Natural Form and History

Natural Ijen Crater Indonesia - Natural history

Ijen volcano in its earliest avatar was part of a stratovolcano named Old Ijen, formed 300,000 years ago. Repeated eruptions saw it grow to over 10,000 feet and there is a considerable layer of lava and pyroclastic deposits from Old Ijen over the underlying Miocene limestone. A caldera, measuring 10 miles in diameter was formed around 50,000 years ago after several explosive eruptions.

Ijen volcano remains as one of the stratovolcanic peaks that dot the Old Ijen caldera and forms part of its eastern margin. It remains an active volcano even today. The highest point in this caldera complex is actually called Mount Merapi (2,799m), meaning “mount fire maker”, which is not to be confused with the other Mount Merapi (2,930m) next to Yogyakarta in Central Java. The Ijen Crater sits at just this below Mount Merapi. 


Natural Ijen Crater Indonesia - Climbing history

Today, the Ijen crater is an active sulphur mine that has been operational since 1968. It was in the 1950’s that locals first started talking about the other-worldly blue flames that lit up the caldera at night. But its attraction as a tourism destination came about after National Geographic did a feature on the volcano specifically talking about the blue flames that the volcano is now famous for.

Natural Ijen Crater Indonesia - Current status

Ijen crater is now a must-do on the itinerary of most visitors to this remote part of Indonesia – as long as they are physically fit and able to handle some exposure to toxic smoke in small quantities (although most only go close to the flames in gas masks). Considering that the natural phenomenon of blue fire is only visible in one other place on Earth – Iceland – it is not surprising that more and more people are getting over their squeamishness about the inhospitable terrain every year to make the trek into the caldera in the dark (the blue fire is only visible at night) and return after catching the brilliant sunrise over the mountains.

Climbing Ijen Crater Indonesia - Climbing Experience & Itinerary

Climbing Ijen Crater Indonesia - Climbing Experience

The trek up Mount Ijen and down into its caldera takes less than 2 hours on average. It does not require special equipment or training but unlike other visitor-friendly locations, this trek can be a bit of a challenge considering it is also an active mine with about 300 men working to mine sulphur in the early hours of the morning along the narrow trail which is also quite steep. There are two parts to the trail – the uphill trail from Paltidung, while steep and jagged in places, is easy to follow. The more challenging section is descending into the crater itself.

Climbing Ijen Crater Indonesia - Trail options

Number of options

Since the highlight of this trip is watching the electric blue flames in the dark, most hikers begin the trek in the middle of the night and catch sunrise from the middle of the caldera, and return in time for breakfast.

Time to complete
6.5 hours

To best achieve the Blue Fire, sunrise, and early breakfast trifecta, your best option is the Paltuding trail. 

Number of days
Day 1

Arrive at Paltuding to get a permit for the climb


Begin walking. The first kilometer is not too hard. The trail is moderately wide and flat with some shrubbery along the sides. The second kilometer is the most difficult in terms of the terrain as well as the incline and by then the vegetation gives way to barren rocks. The third kilometer is again a moderate climb. But add in the darkness, the narrow trail and the (at times) long line of tourists as well as miners and it becomes easy to get separated from your group. You are also likely to start smelling the sulphur in the air early on in the trek as well as feel some stinging in the eyes. The good news is that there is only a single trail that is clearly marked out so you should be able to catch up with your group soon enough.


Start walking down into the volcano once you’re at the edge of the crater. There is a descent of about 800m into the crater itself. There are handrails for support in some stretches but not all. You may need to hold on to rock surfaces around you. The sulphur fumes from the active volcano beneath are also more intense now and this is where you really need to watch out so you are not overwhelmed by the toxic fumes. At some point your guide will give you gas masks for protection.


If you get to the source of the sulphur emissions before sunrise, watch the blue sulphur flames shooting up. You will be a few 100 metres from the edge of the largest acidic crater lake in the world, as sulphur vapours and moton sulphur pour out of the crater around you.


Catch the sunrise from the crater rim, and begin your walk back up along the inside of the crater edge, and back to Paltidung.


Arrive back at Paltidung.

Climbing Ijen Crater Indonesia - Support facilities

Guides and porters

Guides are recommended
Porters are not required

Trail facilities

Trail head - Registration kiosk
Trail head - Toilets / Bathrooms
Trail - Rest stop shelters, such as huts, pavilions, etc.
Trail - Built-in hand-holds, guide-ropes, and hazard markings at technically difficult sections
Summit base camp - Toilets / Bathrooms

Food & water

Trail head - Food
Trail head - Potable water

Network connectivity

Trail head - Network signal

Climbing Ijen Crater Indonesia - Safety & Accessibility


Indonesia has an average temperature of 28 degrees celcius throughout the year but in the mountainous areas this tends to go down, especially at night. At Mount Ijen, the days are pleasant but the nights can get really cold. Temperatures can go down to the range of 5 to 10 degrees Celsius. When planning your trek, aim for the dry season between May and September. If you intend to catch a glimpse of the blue flames, you’ll have to be at the crater by at least 4 am. The flames start to disappear as sunlight starts streaming in by 5 am.

Climbing safety

Toxic fumes:  Sulphurous fumes are a given on this mountain and everyone has some level of coughing and stinging of the eyes so it is not advisable to attempt this if you have a history of breathing difficulty or sensitive eyes. Inside the caldera the fumes are far stronger and there is a distinct possibility that at some point the wind will blow the fumes right into your face. It is important to carry appropriate gas masks and maybe even something like skiing goggles to protect your eyes. Stay calm and patient until the wind blows the fumes in another direction.

Slips and falls:  The rocks up along the inner edge of the caldera have sharp edges and can be challenging to navigate. You’ll need to take big steps on your way up and down so walk carefully and make sure you use your hands for balance. Walking sticks will not help as your hands much more, so make sure you have a good thick pair of gloves for protection.

Personal safety

This is a busy trail frequented by visitors and locals both so there are no major personal safety concerns. However, it is also carried out in utter darkness so there is a possibility that at some point you may get separated from your group. It is essential to stay calm and move forward sticking close to other trekkers on the trail.

Permits, Fees, and Regulations

Yes, there is a permit needed for this hike. The office for issuing permits is right at the entrance of the trail and opens at about 1 am to accommodate those trying to see the blue fire.

Emergency contacts

Police: 110

Fire: 113

Ambulance: 118

Getting there and away

Bali and Surabaya are your nearest airports. Most tour operators will pick you up from Surabaya or Bali. If you are driving on your own from Bali, you will need to first get to Gilimanuk (a 4 to 5 hour drive depending on the traffic and road conditions) from where you can take a ferry to Ketapang in East Java. From the Ketapang harbor it is a 2-3 hour ride to Paltuding. The last stretch is a rugged path and it would be best to hire a 4×4 drive for this bit.

Money Matters

Locals pay IDR 5,000 on weekdays and IDR 7,500 on weekends. Foreigners pay IDR 100,000 on weekdays and IDR 150,000 on weekends.

Climbing Ijen Crater Indonesia - Special Tips

Tips for amateur climbers

The climb doesn’t require any particular mountaineering skills. However, it can be strenuous if you’re not physically fit, specially during the narrow and difficult climb from the crater rim to the caldera lake.

Tips for advanced climbers

If you are fit, Ijen may not pose much of a challenge for you. Combine the experience with a trek up Mount Bromo and you get to see two different volcanoes offering completely different landscapes.

Tips for women

Women climbing the Ijen Crater should not face any special challenges. However, it is best to travel in groups and use a professional and reputable guide or tour service. Avoid unwanted attention or cultural faux pas by taking your dressing cues from locals.

Tips for responsible / safety-conscious climbers

The sulphur mining activity in and around the Ijen Crater is interesting, but its best not to get in their way, and try not to take photos of people without their permission.

Tips for trail runners

Ijen Crater is a popular spot for trail running, with a few races set to take place in August.

Tips for nature lovers

The geological aspects of Ijen are probably the most interesting natural phenomena to learn about and observe. Otherwise, the landscape is dryer and more barren than most other parts of Indonesia.

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