Kawah Ijen is a volcano at the eastern end of Java with a crater lake of around one square kilometre that is the largest highly acidic lake in the world, turquoise and with a pH close to zero. Sulphuric gases vent from fissures at the lake edge, and at night, when they ignite on contact with air, they burn an electric blue. It is one of a very small number of places on earth where this is visible, which is why people climb the mountain at one in the morning.
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The other thing happening in that crater is a sulphur mine. Men break solidified sulphur off the pipes by hand and carry baskets weighing sixty to ninety kilograms up the crater wall and then three kilometres down the mountain, several times a day, for a few dollars a load, mostly without respiratory protection. You will pass them on the path. Pack for cold, for gas, and for a genuinely hard night walk.
What Makes Kawah Ijen Different to Pack For
The gas is the reason for the kit
Sulphur dioxide and hydrogen sulphide vent unpredictably and the wind shifts. In the crater the concentration can become dangerous within seconds. A proper respirator with acid gas cartridges is what the situation calls for; the cloth masks handed out by some guides are close to useless against SO2.
Guides rent gas masks at the trailhead and the quality varies enormously. If you have asthma or any respiratory condition, this trip is a genuine risk and worth reconsidering rather than managing.
It is cold, which surprises everyone
The rim is at around 2,400 metres and you arrive there in the middle of the night. Temperatures at the top run 5°C to 10°C and sometimes lower with wind, which nobody expects in Java. People turn up in shorts and a t shirt because it was 30°C in Banyuwangi.
A merino wool base layer for women is the right answer, because you sweat heavily on the climb and then stand still in cold wind at the top, and cotton in that sequence makes you genuinely cold.
The climb and the descent are both hard
Around three kilometres and 500 metres of ascent to the rim on a loose, steep, dusty track, then a scramble down into the crater on rough rock for the blue fire. The descent into the crater is the dangerous part and it is done in the dark.
Recommended Tours and Experiences
The Kawah Ijen Packing List
Footwear
Waterproof hiking shoes or boots with ankle support and a real sole. The track up is loose volcanic gravel that slides under you on the descent, and the crater route is broken rock. Trainers are what most visitors wear and are the reason most of the ankle injuries happen.
Clothing
Layers, and more warmth than any Java packing list would otherwise suggest: base layer, fleece or insulated mid layer, and a windproof shell. A hat and light gloves. You will be too hot climbing and cold at the top, which is what a layering system is for.
Indonesia is largely Muslim and East Java is conservative, so cover shoulders and knees in the villages and at the accommodation, though on the mountain nobody minds what you are wearing.
The mask
Bring your own respirator if you can: a half face mask with acid gas cartridges. If renting, check the seal and the cartridge date rather than accepting whatever is handed over. A damp bandana over the face is a last resort, not a plan.
Light and practical
A head torch with fresh batteries and a spare set, because the whole ascent is in the dark and a hand held torch leaves you without a hand on the scramble. A power bank. Cash for the park entrance, which is higher at weekends, and for the guide.
A packable rain jacket, since the mountain makes its own weather, and a wide brim sun hat for the descent, which happens in full sun.
Medical
Basic first aid. Eye drops, because sulphur gas stings eyes badly and contact lens wearers suffer; glasses are the better choice. Any asthma medication, and a serious conversation with yourself about whether to go at all if you use it.
What to Wear at Key Sites
The night ascent and the blue fire
Most groups start between midnight and one, reach the rim in around ninety minutes to two hours, and descend into the crater for the flames before dawn, when the light kills the effect.
Practically: the crater descent is steep, loose and crowded with people coming the other way, including miners carrying loads who have right of way and cannot stop. Step aside for them. The gas comes and goes; when it comes, move, do not photograph. Some operators now restrict or prohibit the crater descent depending on conditions, and that restriction should be respected rather than negotiated around.
The rim at sunrise
After the flames fade, the sun comes up over the turquoise lake, which is the other reason to be there and is safer, easier and for many people the better experience.
Practically: cold and windy on the rim. This is where the warm layer earns itself. The rim walk gives views across to Mount Raung and the Baluran plain.
The miners
You will meet them on the path. Some sell small sulphur carvings, which is a reasonable thing to buy. The work has shortened many lives and the wages are very low relative to the risk.
Practically: ask before photographing people, and do not photograph anyone who has not agreed. If you want to help, buying a carving at the asking price or tipping a guide well does more than anything else available to you.
Banyuwangi and around
Banyuwangi is the base town, with the ferry to Bali from Ketapang, and the Baluran national park and Sukamade turtle beach are within reach. Bromo is a long drive west and is usually combined into the same trip.
Practically: most Ijen trips run from Banyuwangi or as an overnight from Bali or Bromo, which means very little sleep. Factor in a recovery day.
What Not to Bring
Leave trainers. Leave contact lenses for the crater. Leave a cloth mask as your only protection.
Leave any expectation of guaranteed blue fire, which depends on gas, wind and access on the night. Leave the assumption that Java is warm at 2,400 metres at three in the morning.
Essential Resources for Women at Kawah Ijen
Emergency numbers in Indonesia: 112 is the national emergency number. Police 110, ambulance 118 or 119, fire 113. On the mountain, your guide and the park rangers are the emergency service, and evacuation is on foot or by the wheeled carts the miners use.
Tourist support: Indonesia operates a tourist information line on 1500 015. There is a police presence in Banyuwangi. A stolen passport needs a police report before the embassy can issue a replacement.
US Embassy and consulate: the embassy is in Jakarta at Jalan Medan Merdeka Selatan 3-5, telephone +62 21 5083 1000, at id.usembassy.gov. The nearest consular presence to East Java is the consulate general in Surabaya. Enrol in the Smart Traveler Enrollment Program at step.state.gov before you travel.
Main hospital or clinic: Banyuwangi has hospitals including RSUD Blambangan, around an hour from the trailhead. There is nothing on the mountain. Anything requiring specialist respiratory or trauma care means Surabaya, six hours away, or Bali. Travel insurance covering trekking and volcano visits is essential, and worth reading closely since some policies exclude visits to active volcanoes entirely.
Official health authority: the Indonesian Ministry of Health at kemkes.go.id.
US State Department travel advisory for Indonesia: current advisory level and detail. Read it directly rather than relying on this page.
UK FCDO travel advice for Indonesia: entry requirements, safety and health guidance, which carries specific guidance on volcanoes.
Official tourism authority: Wonderful Indonesia at indonesia.travel. Volcanic status is published by PVMBG, the Indonesian volcanology agency, and Ijen has been closed to visitors at times on their assessment; that status is the thing to check before booking anything.
Solo women safety assessment: the human risk at Kawah Ijen is low and the environmental risk is high. Guides are licensed, groups on the mountain are large and international, and the trail at one in the morning is busier than most city streets. Harassment is not a meaningful concern, Banyuwangi is a quiet regional town, and women do this trip alone routinely, usually by joining a group through their accommodation, which is the sensible arrangement. What can hurt you is the mountain. Sulphur dioxide is genuinely dangerous: it has killed miners, it causes lung damage at concentrations reached in the crater, and the wind shifts without warning. If the gas comes, leave rather than waiting for a photograph, and do not go into the crater at all if you have asthma or any respiratory condition. Get a real mask rather than the cloth one. The second risk is the terrain in darkness: the crater descent is loose rock on a steep gradient with a queue moving both ways, and falls happen every season. The third is fatigue, since most people arrive having not slept and then walk uphill for two hours at altitude. Go with a guide, keep your torch on your head rather than in your hand, step aside for the miners, and accept that the blue fire is not guaranteed and is not worth taking a risk for.
Reading On
Kawah Ijen is one of the most extraordinary things you can see in Indonesia and one of the few destinations where the honest advice includes reconsidering whether to go into the crater at all. The Indonesia travel guide for women is the parent for the whole country and covers the islands, the seasons and the transport, and the Indonesia packing list for women covers a multi island trip. West on Java, the Yogyakarta packing list for women covers the cultural centre and the Jakarta packing list for women the capital. East across the strait, the Bali travel guide for women and the Lombok travel guide for women cover the islands most Ijen visitors come from or go to next. For other Indonesian wilderness, the Bukit Lawang packing list for women covers the Sumatran rainforest and the Bunaken packing list for women the reefs of North Sulawesi. The travel packing guide for women is the parent for all destinations. For why merino is right when you sweat uphill for two hours and then stand still in cold wind, the best merino wool base layers for women explains the fibre, and the Roman Trail collection is where the tops themselves live.
If the outer journey is calling you, the inner one usually is too. Explore SoulMap at romantrail.com/blogs/soulmap.
