The Sunda Strait is back in the headlines after Mount Anak Krakatau entered a continuous eruption phase, sending an ash column straight into one of Indonesia's busiest flight corridors. Booms audible for hundreds of kilometers and lava fountains rattled coastal communities in Banten and Lampung, while overhead, airlines began cancelling and diverting flights one after another.

The Anak Krakatau eruption since September 4, 2026 has forced several airports in Jakarta, Lampung, and Bandung to close temporarily. If your trip touches one of these airports, you can check your Flight Status directly on Traveloka to see whether your schedule has changed.

Activity at Mount Anak Krakatau, in the Sunda Strait, escalated overnight from Friday, September 4 into Saturday, September 5, 2026. The volcano is now at Alert Level III (Siaga), Indonesia's second-highest alert tier. Indonesia's Geological Agency has barred residents, tourists, and climbers from a 3-kilometer radius around the crater.Volcanic ash has been tracked spreading across Banten, Greater Jakarta, West Java, Lampung, and Bengkulu, based on monitoring by Indonesia's meteorological agency (BMKG) and satellite analysis from Himawari-9 and the Darwin Volcanic Ash Advisory Centre.

Under NOTAM No. A3341/26, flight operations at Soekarno-Hatta International Airport were first suspended at 1:30 AM local time on Sunday, September 6, 2026. The closure has since been extended multiple times:

Halim Perdanakusuma Airport (HLP) in Jakarta carries the same closed status and timeline.Because these windows are updated several times a day, treat the hours above as an indication of the trend rather than a guarantee of when flights will resume.

According to an official BMKG (Indonesia's Meteorological, Climatological and Geophysical Agency) press release issued September 7, 2026, a physical "paper test" conducted at 7:00 AM confirmed volcanic ash residue at multiple airports. Eight airports across Sumatra and Java were initially closed — but their status is not uniform. As of the latest AirNav Indonesia NOTAM update this afternoon, one airport has fully reopened, while seven remain closed:Current Status

(WIB = Indonesia Western Standard Time, UTC+7. All estimated reopening times are approximate and subject to change.)

Important caveats:

BMKG reported that ash at lower altitudes (up to 15,000 feet/4.57 km) is drifting west at roughly 15 knots, covering parts of Banten, the southwestern part of West Java, Lampung, and Bengkulu. At higher altitudes (up to 50,000 feet/15.24 km), the ash plume is actually being observed moving away from Indonesia toward the Indian Ocean.Since the first eruption on September 4, 2026, BMKG has issued 39 SIGMET (Significant Meteorological Information) bulletins to support aviation safety decisions.

Not every airport in Indonesia is affected. Ngurah Rai International Airport in Bali, for instance, continues to operate normally overall. According to airport officials and Bali Governor Wayan Koster (September 7, 2026):

This pattern likely applies to other airports outside the ash-affected corridor (for example, Makassar, Medan, or Manado): normal operations, with disruption limited to routes directly connected to the closed airports in Java/Sumatra.

BMKG has confirmed the Sunda Strait crossing route remains safe. HF Radar monitoring at Carita and Tanjung Lesung, as of 8:00 AM on September 7, put the probability of a tsunami in the low category (below 50%). Monitoring from 20 tsunami gauges around the Sunda Strait also detected no sea-level anomalies. Wave heights in the strait are forecast at 0.5–2.0 meters over the coming week (September 8–13, 2026), with generally sunny to partly cloudy weather.

According to figures released by Soekarno-Hatta Airport management:

Indonesia's disaster management agency (BNPB) has stated there is no imminent tsunami risk from the current eruption, and the government is planning cloud-seeding operations to help wash volcanic ash out of the atmosphere more quickly.

The Ministry of Transportation has activated several alternative airports for 24-hour operations to absorb flights that cannot land at or depart from Soekarno-Hatta:

Kertajati is geographically the closest to Jakarta and has already received diverted international flights, including Garuda Indonesia services from Jeddah and Madinah. The decision to use an alternative airport rests with each airline; passengers can choose to continue their trip via the substitute airport or cancel their flight.

The government has confirmed there is no extra charge for onward transport between the alternative airports and Jakarta:

Traveloka maintains a dedicated page listing affected airlines along with each one's refund and reschedule policy in real time: Flight Disruption Info: Anak Krakatau Eruption.That page lists, airline by airline, the affected routes and flight numbers, the requirements for filing a refund or reschedule request, and compensation details. Airlines already listed there include:

Because each airline's cancellation status and policy is different and continues to be updated, the fastest way to confirm whether your flight is affected — and which refund or reschedule options apply — is to check that page directly using your airline and flight number.

For the current status, these sources are worth more than news aggregators (including this article):

Note: the information in this article is based on official data as of September 7, 2026, and may change at any time as the situation on the ground develops.