Mount Ijen (Ijen Crater)

2,350m (7,710 ft) (at the crater rim)

The trek up Mount Ijen and down into its caldera takes less than 2 hours on average, and about 6.5 hours in total to complete.

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.

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 the sunrise from the middle of the caldera, and then return in time for breakfast.

The most popular trail used to do this trek is called the Paltuding Trail, as this is the best trail to catch site of the main allure; the Blue Fire.

The first kilometre (0.6 mi) is not too hard. The trail is moderately wide and flat with some shrubbery along the sides.

The second kilometre (1.2 mi) is the most difficult in terms of the terrain as well as the incline. By this point, the vegetation gives way to barren rocks.

The third kilometre (1.89 mi) 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, and it is clearly marked out so you should be able to catch up with your group soon enough.

Once you’re at the crater’s edge, you’ll start walking down into the volcano. There is a descent of about 800m (2624.67 ft) 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, you can watch the blue sulphur flames shooting up. You will be a few 100 metres ( about 1000ft) 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.

Indonesia has an average temperature of 28°C (82.4°F) 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°C (41°F – 50°F)

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.

This trek does not require special equipment or training, however, it is important to carry appropriate gas masks and maybe even something like skiing goggles to protect your eyes from the gas and fumes, as well as a good thick pair of gloves for protection against sharp rocks.

At the trailhead, you’ll find a registration kiosk, toilets/bathrooms, food and potable water.

Along the trail rest stop shelters are available, there are handrails on some stretches, and the trail is clearly marked.

At the summit base camp, there are toilets/bathrooms.

Guides are recommended, especially since you will most likely be attempting the trek in the dark. Porters are unnecessary, as this is a short hike.

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 there you can take a ferry to Ketapang in East Java. From the Ketapang harbour, 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.

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.

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 but your hands will help much more, so make sure you have a good thick pair of gloves for protection.