Bali sits on a chain of volcanic islands, and that geology can reach into a holiday plan at short notice. Ash from an eruption can close Ngurah Rai airport in Denpasar or ground flights for days. It does not even need to be a volcano on Bali itself. An eruption on a neighbouring island has cancelled flights between Bali and Australia before.
This guide explains why ash stops planes and what has happened in the past. It also covers what you can do before and during a trip if a volcano becomes active. The aim is to help you plan calmly rather than worry. A little preparation makes an unexpected delay far easier to handle.
Why Indonesia has so many active volcanoes
Indonesia has more than 120 volcanoes, and 76 of them are considered active. The Australian Government’s travel advice says any active volcano could erupt at any time. Activity can also escalate with little or no notice. On Bali, the best known are Mount Agung and Mount Batur, which are both popular with trekkers.
The wider region is just as busy. The Darwin Volcanic Ash Advisory Centre watches 152 active volcanoes across Indonesia, Papua New Guinea and the southern Philippines. That gives a sense of how often ash can drift into flight paths. A volcano on another island can still affect your flight home.
Why volcanic ash grounds aircraft
Volcanic ash is not soft like smoke from a bushfire. It is made of tiny pieces of rock and glass. According to the Bureau of Meteorology, ash can melt inside a jet engine and fuse into a glassy coating on its parts. That can cause a loss of thrust and even engine failure.
Ash also wears away engine and body parts and can clog fuel and cooling systems. Indonesia provides a famous example. In 1982 a British Airways 747 lost all four engines after flying through ash from Mount Galunggung. The crew restarted some engines and landed in Jakarta. Three weeks later a Singapore Airlines 747 lost two engines and also made an emergency landing.
Aviation now relies on a global warning system for ash. There are nine Volcanic Ash Advisory Centres around the world, and the Darwin centre run by the Bureau covers Indonesia. It operates around the clock, using satellites, ground observations, pilot reports and forecast models. After an eruption it issues advisories every six hours, or more often if conditions change.
Each advisory shows where the ash is, how high it sits and where it is likely to move over the next 18 hours. Pilots flying over volcanic areas must check these and monitor updates during the flight. Airlines then decide whether to fly using their own risk policies. That is why one airline may cancel a Bali service while another keeps flying.
What has happened in Bali before
In November 2017 Mount Agung erupted in eastern Bali. About 150,000 residents were evacuated and Denpasar airport closed because of ash fall. One Australian traveller said her group was stranded for more than a week. Others spent the night waiting at airports on the way home, including Darwin.
A more recent example came from outside Bali. In June 2025 Mount Lewotobi Laki-laki on the island of Flores erupted. Airport operators in Denpasar reported 87 affected flights, including routes to Perth, Darwin, Adelaide, Melbourne, Sydney, Brisbane and the Gold Coast. Indonesia’s transport ministry said about 14,000 travellers were affected.
Authorities raised the volcano’s alert to its highest level and evacuated two villages. The airport later reopened, but operators warned that further disruption was possible. It showed how one eruption on a neighbouring island can upset thousands of holiday plans.
Before you travel
Good preparation makes an eruption much easier to manage. Buy travel insurance when you book your trip, not the week before you leave. Consumer group CHOICE has warned that once an eruption becomes a known event, it is generally too late to buy cover for it. An event usually becomes known once it appears in the media or on official sites such as Smartraveller.
Read what your policy says about natural disasters, delays and extra accommodation. Smartraveller advises that the Australian Government will not pay overseas medical or evacuation costs. It also says that if you cannot afford travel insurance, you should not travel. Check that the policy covers your whole trip, including any stopovers.
A little extra planning goes a long way. Think about what would happen if you were stuck for a few extra days. These simple habits make that much easier:
- Keep some room in your budget for extra nights of accommodation.
- Carry enough of any regular medication for a few extra days.
- Save your airline and insurer details where you can reach them offline.
- Avoid tight connections or important appointments straight after you land.
- Sign up for airline alerts so schedule changes reach you quickly.
If your trip is built around a fixed date, allow extra margin. That applies to anyone weighing up the pros and cons of travelling to Bali for dental treatment, where follow up appointments matter. It also applies to weddings, tours and other bookings you cannot easily move. Checking the weather seasons of Bali helps you pick dates, though a volcano can become active in any month.
A delay also means more time in transit with your belongings. If you are carrying anything valuable, think about how you would manage an unplanned extra stay. Our answers to common questions about travelling with jewellery are worth reading before you pack.
If a volcano becomes active during your stay
Stay calm and get your information from official sources. Contact your airline directly for flight updates rather than relying on social media. Follow the instructions of local authorities, who may order evacuations at short notice. Smartraveller also suggests checking Indonesia’s four level volcano alert system and local media before visiting any volcanic area.
Respect exclusion zones around a volcano, as these can change quickly. Treks and day trips near an active crater may be called off. Outdoor plans such as canyoning in Bali could also change if conditions turn, so keep your schedule flexible.
Ash can affect your health as well as your flights. The World Health Organization lists breathing problems from falling ash and gases, eye and skin irritation and contaminated food and water among the health effects of eruptions. If ash is falling, follow local health advice and see a doctor if you have trouble breathing.
Keep in touch with family at home so they know you are safe. Let your insurer know early if your flight is cancelled, as policies have their own rules about claims. Keep receipts for meals, transport and extra nights, since you may need them later.
Frequently asked questions
Can a volcano outside Bali close Bali’s airport?
Yes, it has happened. In June 2025 an eruption of Mount Lewotobi Laki-laki on Flores affected 87 flights at Denpasar. Ash clouds move with the wind, so distance alone does not protect a flight path.
Who decides whether my flight goes ahead?
Your airline makes that call. It uses volcanic ash advisories and its own risk policies. Contact the airline directly for the latest information on your booking.
Is it too late to buy insurance once an eruption starts?
For that event, it often is. CHOICE says cover for a specific event generally cannot be bought once the event becomes known. Buying a policy when you book your trip is the safest approach.
Should I cancel my Bali holiday because of volcanoes?
Not usually, but stay informed. Check Smartraveller and your airline before you leave and during your stay. Follow exclusion zones and local advice if activity increases.
This article is general information only and is not travel, insurance or medical advice. Conditions change quickly, so check Smartraveller, your airline and local authorities before and during your trip.
