In short. BMKG is responsible for warnings: install the Info BMKG app, which sends alerts about quakes and tsunami. The 20-20-20 rule: if the ground shakes for longer than 20 seconds, you have about 20 minutes to climb 20 metres, and you should not wait for a siren or a message. There are three alert levels: Waspada, a wave up to half a metre (leave the beach), Siaga, 0.5 to 3 metres (evacuate), and Awas, above 3 metres (full evacuation). Bali has nine sirens, tested on the 26th of every month at 10:00. At any other time a siren is real. From the low beaches of Kuta, Seminyak and Sanur, people walk inland on foot, following the Jalur Evakuasi Tsunami arrows. If you stay in a hotel, ask in advance which floor and which staircase are used for evacuation.
Who warns you. In Indonesia, BMKG, the state agency for meteorology, climatology and geophysics, is responsible for earthquakes and tsunami. Its early warning system InaTEWS issues a message about a possible tsunami a few minutes after a strong quake. Install the Info BMKG app, available in the App Store and Google Play. It sends alerts about earthquakes with the distance from your location, storm warnings and all-clear messages. BMKG contact centre: 196.
The 20-20-20 rule. This is the BMKG formula for people on the coast: if the ground shakes for longer than 20 seconds, you have about 20 minutes to climb to a height of 20 metres or more. BMKG repeats it at meetings with coastal communities. In June 2026 it did so in Baubau: shaking longer than 20 seconds is the first danger signal, you have about 20 minutes before a local tsunami arrives, and you should climb at least 20 metres above sea level. Where the wave arrives faster, within minutes, as in Maluku, the formula does not work, warned BMKG head Dwikorita Karnawati: leave immediately after the shaking. A strong, long quake near the sea is itself the order to leave: do not wait for a siren or an alert. If there is no high ground nearby, a sturdy tall building away from the water will do, third floor or higher. The national disaster agency BNPB notes that for flat areas such as southern Bali the height can be lowered to 10 metres, but higher is always safer.
Three alert levels. BMKG estimates the expected wave height and assigns a status, as Kompas explained citing the agency:
- Waspada, yellow: a wave below half a metre. Leave the beach and river mouths.
- Siaga, orange: 0.5 to 3 metres. Evacuate.
- Awas, red: above 3 metres. Full evacuation.
Go back to the shore only after BMKG announces the end of the alert. It arrives in the same app.
Beach sirens. Bali has nine tsunami warning sirens, run by the provincial BPBD: Kuta, Seminyak at Double Six beach, Kedonganan, Tanjung Benoa, Nusa Dua inside the ITDC area, Sanur at Matahari Terbit beach, Serangan island, Tanah Lot and Seririt in the north. They are tested on the 26th of every month at 10:00 Bali time (BPBD report on the regular test): the siren sounds, and an announcement in Balinese, Indonesian and English says it is a test. A siren at any other time is real: move away from the water at once, without waiting for details. Daryono, BMKG director for earthquakes and tsunami, puts it this way: a siren is not a warning, it is an evacuation order.
Where to go. In coastal villages there are Jalur Evakuasi Tsunami signs, with arrows leading from the shore to assembly points. On Serangan there is a temporary evacuation building (TES) about 15 metres high: the two upper floors are set aside as shelter, and according to an estimate in a report citing BPBD it holds about two thousand people, while the ground floor is used by a market. Kuta, Seminyak and Sanur have no hills, so people go inland on foot, following the arrows, not by car: the roads will jam in the first minutes. If you live or stay in a hotel by the sea, ask at reception which floor and which staircase are assigned for evacuation. It takes a minute, and in Bali it is rarely asked.
During the shaking. Indoors: get under a sturdy table, cover your head, hold on, and stay away from glass and wardrobes. Do not run outside while it is shaking: most injuries come from falling objects at the exit. When it stops, leave by the stairs and do not call the lift, as BMKG advises on its InaTEWS page. On a scooter: stop away from poles, trees and signs. On the beach: as soon as it stops, move away from the water. If the sea suddenly pulls back and exposes the seabed, that is not a sight to watch, it is a signal to run.
What to keep at home. A small bag by the door: copies of your passport and KITAS, water, a power bank, a torch, medicines, cash. Know where the gas is shut off. Agree a meeting point with your family in case communication goes down. On your phone: Info BMKG, the number 112 and our guide to emergency numbers.
What this means for you. Most tremors in Bali are harmless, but the southern beaches, where most newcomers live, lie low. Remember one thing: if it shakes for longer than 20 seconds, go up and inland and do not wait for messages. The rest, the app, the sirens and the staircase in your hotel, can be sorted in one evening while everything is calm.