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Jakarta, Java, Sumatra

Anak Krakatau and Semeru Eruptions Disrupt Travel Across Java and Sumatra

Volcanic ash from two simultaneous eruptions is blanketing cities from Jakarta to East Java, closing airports and hiking trails and raising serious health concerns.

Qontaktly Editorial·September 7, 2026·3 min read
Key takeaways
  • Anak Krakatau has been erupting continuously since Friday, September 5, 2026, spreading ash across Jakarta, western Java, and parts of Sumatra.
  • Soekarno-Hatta Airport and up to eight other Indonesian airports faced closures, affecting an estimated 166,000 passengers.
  • Volcanic ash contains silica particles that pose genuine health risks to eyes, skin, and the respiratory system, according to epidemiologist Dicky Budiman of Griffith University.
  • Mount Semeru in East Java also erupted on Sunday, with forest fires burning more than 3,000 hectares inside Bromo Tengger Semeru National Park and all hiking trails closed.
  • The Indonesian government waived overstay fees for stranded foreign nationals and ordered airlines to offer refunds and rescheduling options.

Two Active Volcanoes Putting Indonesia's Travel Corridor on Alert

Indonesia is managing simultaneous volcanic emergencies on two fronts. As of the morning of Sunday, September 6, 2026, ash from the erupting Mount Anak Krakatau in the Sunda Strait had drifted across western Java, including Jakarta and its surrounding metropolitan area, and reached parts of Sumatra. At the same time, Mount Semeru in East Java sent an ash column 1,000 meters above its summit while forest fires continued burning across the mountain's slopes.

The situation is fluid and affects travelers across a wide geographic band.

What Is Happening at Anak Krakatau

According to MAGMA Indonesia, the official monitoring platform of the Ministry of Energy and Mineral Resources, Anak Krakatau had been erupting continuously since the Friday morning before the weekend. Seismographs recorded eruption events at 05:53 and 07:10 WIB on Sunday alone. Incandescent lava was visible from Pasauran in Serang Regency, Banten, as early as September 5.

The ashfall reached Greater Jakarta (Jabodetabek) and prompted police to distribute masks to residents. Soekarno-Hatta Airport faced closure, and at various points during the crisis eight airports across the region were shut, with authorities working to keep five others operating around the clock. The government also waived overstay fees for foreign nationals stranded by the disruptions.

Health Risks: Volcanic Ash Is Not Ordinary Dust

Epidemiologist Dicky Budiman of Griffith University in Australia, as quoted by ANTARA on September 6, stressed that volcanic ash carries risks well beyond those of common particulates. The ash contains silica particles that function like microscopic glass shards, capable of damaging the eyes, nose, mouth, and skin on contact. Anyone in affected areas should treat ash exposure as a genuine health hazard, not a minor inconvenience.

Mount Semeru: Trails Closed, Fires Spreading

Semeru, Java's highest peak, was already under restrictions before Sunday's eruption. Forest fires have burned more than 3,000 hectares within the Bromo Tengger Semeru National Park (TNBTS), according to park data reported by Antara. Hiking trails remain closed, and the combination of active eruption and ongoing wildfire makes the mountain inaccessible and unsafe for visitors.

Why It Matters for Hosts

Independent operators in Jakarta, Banten, and East Java should act on several practical fronts immediately. First, proactively contact guests with upcoming bookings to share official health guidance on ash exposure and mask use. Second, check whether your property sits in an ashfall zone and communicate any service adjustments, such as keeping outdoor spaces closed or providing masks on arrival. Third, review your cancellation and rescheduling policies: the Indonesian government has already directed airlines to offer refunds and rescheduling, and guests will expect similar flexibility from accommodation providers. Staying ahead of guest concerns with clear, calm communication will protect both relationships and reputation during a period when travel confidence is fragile.

For the latest eruption status, monitor MAGMA Indonesia directly at the Ministry of Energy and Mineral Resources portal.

The details in this post were first reported by Tempo English (Tempo.co) on September 7, 2026.

First reported by en.tempo.co.

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