Mt Ijen Ultimate Hiking Guide To The Largest Acidic Crater Lake in the World

Sunrise view of Mt Ijen crater

Is Mt Ijen volcanic crater your first ever sunrise hike and not sure if you are up for the challenge? Not to worry, we have put together the ultimate guide to hiking Mt Ijen, which is home to the world’s largest acidic crater lake in the world!

Is Mt Ijen an active volcano? Is it safe to visit?

This is often the first question we get. Mt Ijen is after all an active volcano in East Java, and its last known eruption was back in 1999. With all active volcanos, there will always be this risk of a sudden eruption that catches us by surprise. A recent example is the Mount Marapi eruption on 3 Dec 2023 that led to casualty. Nonetheless, in comparison, Mount Merapi is much more active a volcano compared to Mt Ijen.

Is this hike safe? Is this hike difficult?

As for the hike, there are two parts to it. The first part of the hike up Mt Ijen is safe, moderately easy and manageable with a push in endurance. The second part of the hike down to the Mt Ijen crater to see the blue flames (see the path circled in red on the map below) is somewhat dangerous and challenging.

The path is steep, has many loose rocks and you are hiking in the dark. Once you reach the blue flames, you will also be engulfed by sulphuric gases. The gas mask helps you to a certain extent. However, when the gas blows towards you, you can smell the sulphuric gas and it can be difficult to breathe normally. Hence, if you are someone who has respiratory problems or does not wear shoes with a good grip, the hike down to see the blue flames will not be for you.

A summary of the time and distance we took for the hike, including the elevation.
The path up and down the crater circled in red.

How cold does it get at Mt Ijen?

Mount Ijen before sunrise temperatures range from 5°C to °C. After the sunrise, the weather goes up to 22°C to 25 °C.

What should I wear for the hike?

The key to the hiking outfit is layering. As the incline at the start of the hike is rather steep, many hikers took off their layers till they were left with a short-sleeved t-shirt. However, at the summit, the wind is very strong and you will be wearing the jackets to stay warm again. The descent down to Mt Ijen has a lot of loose rocks and sand. A pair of shoes with a strong grip is highly recommended.

What should I bring on the hike?

  1. Headlight – The local guide only gave us one torchlight to share between the two of us.
  2. Water
  3. Snack bars – Reward yourself at the summit!
  4. Tissue – Your nose will run after smelling the sulphuric gas. A pack of tissues will come in handy.
  5. Cash – At the Blue Flames, the local guide would ask for donations. These guides brave such extreme conditions daily, a little donation will go a long way.

Do we need to book a tour to hike? What time does the hike start?

The Mt Ijen hike was part of our 4D3N trip Surabaya Indonesia trip with Cheapbromo. Our tour guide picked us up from Ijen View Hotel at midnight. After a 1.5-hour car ride, we arrived at a shophouse located at the base of Mt Ijen. Many visitors grabbed a quick bite and used the toilet. You can rent a hiking stick here too.

For the hike up Mt Ijen, it is a requirement to be accompanied by a local guide. The local guide picked us up from the shophouse and gave us a new gas mask that would come in handy down the Mt Ijen crater. The hike started at 2.10 am. We hiked a total of 11km, up an elevation of 632m and returned back to the shophouse at 7.30 am.

What are the Blue Flames? Will you always get to see the Blue Flames? Is it worth seeing the Blue Flames?

Here is an image of the blue flames during our visit in Oct 2023.

Blue flame of Mt Ijen. East Java Indonesia.
Spectacular blue flames

Sulphuric gases seep out of the cracks in the volcano at high pressure. Once the gases come in contact with air, they combust into these very hot and iconic blue flames. This is a natural phenomenon. However, our tour guide shared that the size and scale of the blue flames are dependent on the mood of the local guides. The guides apparently will further ignite the blue flames. The more donations they receive, the larger the size of the blue flames would be.

Can I see Mt Ijen crater without hiking? Are there other ways of reaching the Mt Ijen crater?

If hiking is not for you, but you would still like to take photos with the most picturesque world’s largest acidic lake, there is a way. At the base of Mt Ijen, you would see a stretch of local guides offering “taxi” service. Depending on the season, it can cost about 1 million IDR/ SGD$85 (negotiable), for the local guides to pull you up and down the mountain on a 3-wheel cart.

When we were there, there were a few tourists who took up this service. We found that many more people took the “taxi” for the way down as they might have been too exhausted after the hike up!

You might think that it is inhumane for the guides to pull these 3-wheel carts as it is such difficult manual labour. However, to these locals, this cart-pulling work is far better than being a sulphur miner. Our guide told us that Ijen sulphur miners are only paid SGD$5 a day, risking their lives breathing in toxic air and hauling very heavy sulphur rocks out of the volcano. Hence, in comparison, one “taxi” job would earn them almost 17 times their sulphur mining job.

Sulphur rocks that miners would have to carry out of the volcanos. Mt Ijen East Java Indonesia.
Sulphur rocks that miners would have to carry out of the volcanos

Here are some Instagram worthy shots we took from the trip!

Mt Ijen acidic lake crater. East Java. Indonesia.
The sun rise revealing the Mt Ijen Lake crater bit by bit.
Couple taking a photo at Mt Ijen acidic lake crater. East Java. Indonesia.
See the sulphuric smoke emerging in the backdrop. That is where we saw the blue flames!
Mt Ijen acidic lake crater. East Java. Indonesia.
Many spots along the Mt Ijen ridge that gives you spectacular photos of the beautiful turquoise blue lake.
Mt Ijen acidic lake crater. East Java. Indonesia.
The geological cracks of a volcano.
Mt Ijen acidic lake crater. East Java. Indonesia.
The view of the surrounding mountains on the way down Mt Ijen.

Other questions?

Hope this post was useful in helping you plan your adventure hike up Mt Ijen. It was definitely the highlight for our 4D3N getaway to Surabaya, Indonesia. Comment below to share with us your thoughts or if you have any questions. We will try our best to address them and add them into this list of FAQs we have put together!

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