Ijen Crater night hike: blue fire, acid lake and gas safety from Banyuwangi

What the Ijen night hike involves

Ijen rises to 2,386 metres, according to Indonesia's volcanology agency (PVMBG). It stands on the edge of a vast old caldera that the Ministry of Tourism puts at 134 square kilometres. Since 2023 it has been the main attraction of the Ijen UNESCO Global Geopark, which covers 4,723 square kilometres. Around 22 younger volcanic cones have grown inside the caldera and on its rim.

The walk starts at the trailhead at Paltuding Post (Pos Paltuding). The ministry's destination page gives the trail as 3 kilometres to the edge of the crater. A newer ministry article describes a trek of about 3.8 to 4 kilometres taking two to three hours. Its main Kawah Ijen page says one to one and a half hours. In practice, the time depends on your fitness and on how often you stop on the steep stretches. From the rim you look down onto the turquoise lake, the steaming sulphur vents and the miners' path. You can then walk part of the way around the rim.

When we checked on 3 October 2026, the ministry's Ijen Crater page said the climb opens daily at 01:00, and at 03:00 during restriction periods. It is cold up there. The ministry describes the air at about 10°C on a normal day and sometimes as low as 2°C, so bring a warm jacket and long trousers, as well as water and a snack. The ministry also warns that the sulphur will tarnish silver jewellery, so leave it at your hotel.

Gas, the crater floor and the blue fire: the safety realities

The blue fire is sulphur gas that ignites as it reaches the air. UNESCO's geopark profile explains that Ijen's high sulphur concentrations and temperatures above 360°C produce the blue flames, and that they can only be seen at night because daylight drowns them out. The ministry's guidance is to be there between about 2:00 and 4:00, before first light. The flames burn at the vents inside the crater, near the lake, where the miners work.

This is where you need to slow down. When we checked on 3 October 2026, PVMBG's daily report on its MAGMA Indonesia site (dated 2 October) listed Ijen at Level I (Normal), the lowest alert level. The report still advised visitors not to go down to or approach the floor of the crater, not to camp within 500 metres of it, and to beware of toxic gas around the crater and possible collapse of the crater walls. It also warned of carbon dioxide along the Banyupait–Banyuputih river. If a guide or tour offers to take you down to the flames, remember that the agency advises against it. Ask your guide exactly where they plan to take you, and decide before you start.

Gas is the everyday risk. The ministry strongly recommends a guide because toxic gases can be present around the crater, and the head of the nature park told ANTARA that protective masks are strongly recommended. Bring a proper respirator rather than a cloth mask. If the plume blows towards you, turn back. People with asthma or heart or lung conditions should take medical advice before going.

The park can also close with little warning. On 4 September 2026 the East Java conservation agency (BBKSDA) closed the Ijen Crater Nature Tourism Park until further notice, after forest fires spread towards Pondok Bunder on the hiking route. Banyuwangi declared a 14-day fire emergency. The park reopened on 28 September 2026, with a reminder that lighting campfires is forbidden. Check the latest status before you travel.

How to arrange it: tickets, guides and which side to sleep on

Ijen is a nature tourism park (Taman Wisata Alam) managed by BBKSDA East Java. Entry tickets are sold online. When the park reopened in September 2026, its head told ANTARA that tickets could be booked through the Forestry Ministry's site, ayoketamannasional.kehutanan.go.id. We have not given a price, because we could not confirm the current fee on an official page. Check it when you book, and check whether your tour includes it.

Go with a local guide; the ministry strongly recommends it. ANTARA has reported on a group of Ijen guides based in Licin subdistrict, on the Banyuwangi side, who are now learning Mandarin as well as English. That gives a sense of how busy the trail has become. On the mountain you will also find cart taxis (ojek gerobak), nicknamed 'lamborghini', for visitors who cannot walk the trail or would rather not.

Banyuwangi is the closer and more practical base. The ministry describes it as the starting point for the blue fire, and it is where the airport, the trains from Surabaya and the ferry from Bali arrive. The Osing village of Kemiren lies on the road up to Ijen, according to the ministry, and has homestays; arrange these in advance. Bondowoso is the western approach. The ministry notes that Ijen can be reached through Bondowoso from both the north and the south coast, ending at Paltuding. This side suits travellers coming from the west, for example after Mount Bromo. Whichever side you choose, the ministry warns that the road up is very steep and recommends a sturdy vehicle. That means hiring a car with a driver or booking a tour with pick-up rather than driving yourself.

The sulphur miners

The miners are the reason the crater has paths at all. They walk down into the crater each day, dig out the sulphur by hand and carry it up the crater wall in two baskets slung from a shoulder pole. The ministry describes this traditional hand-mining as a humbling look at the labour behind the local economy.

Remember that they are at work. Give way on the narrow sections, especially on the path inside the crater. Ask before you take close-up photos, and do not stop in their way to take them.

After the hike: Kemiren, Banyuwangi and onward

By mid-morning you will be tired, so plan an easy afternoon. In Kemiren, the Osing people keep their own language, carved wooden houses with three distinct roof shapes, the Gandrung dance and a tradition of coffee roasted over a wood-fired clay stove. The Ministry of Tourism describes cafés where you can learn to roast and brew it, and Osing dishes such as pecel pitik. The ministry puts Kemiren about 40 minutes' drive from Banyuwangi's Blimbingsari airport.

From Banyuwangi, Baluran National Park, with its savanna and herds of banteng, makes a good next stop. The ferry from Ketapang harbour crosses to Gilimanuk in Bali, for Pemuteran on Bali's north-west coast. Heading west, Ijen pairs naturally with Mount Bromo; the ministry's guide to East Java treats Bromo and Ijen as one trip.