BMKG Marine Weather Warning: High Swell Warning for Southern Bali Waters, Badung Strait & Fast Boat Corridors

The Indonesian Meteorology, Climatology and Geophysics Agency (BMKG), Denpasar Regional Branch III, has officially issued Marine Weather Warning Bulletin No. 09/2026. This emergency communiqué warns maritime carriers, fishermen, speedboat captains and coastal users of the arrival of a powerful southern swell generating dangerous waves of between 2.5 and 4.0 meters across the entire southern coast of Bali province.

Ocean dynamics and synoptic conditions

This severe maritime episode is caused by a deep depression system (984 hPa) centered in the southern Indian Ocean. This pressure gradient generates violent south-southwest winds which propel an energetic long-term ground swell (14 to 18 seconds) hitting the Balinese continental shelf head-on. When breaking over shallow reefs and steep cliffs, the phenomenon of mechanical elevation produces breaking waves that can peak at 4.5 or even 5.0 meters.

Maritime corridors under high surveillance

The official bulletin places several strategic sea lanes on reinforced orange vigilance:

• Badung Strait (Selat Badung): Average troughs of 2.5 m to 3.5 m directly affecting the navigation of passenger speedboats (Fast Boats) connecting Sanur to Nusa Penida and Nusa Lembongan.
• South Bali Strait (Selat Bali): Strong swell of 2.5 m to 4.0 m representing a major danger for traditional artisanal fishing boats departing from Kedonganan and Jimbaran.
• South Lombok Strait (Selat Lombok): Very rough seas with waves higher than 3.5 m disrupting the crossing of freight and passenger ferries between Padangbai and Lembar.
• Offshore Indian Ocean south of Bali: Perilous offshore conditions with swells of 3.0m to 4.2m and wind gusts reaching 25 to 28 knots.

Regulation of speedboat traffic in Sanur by KSOP

The maritime port authority (KSOP Benoa and Sanur branch) has activated the maritime safeguard protocol. Depending on the height of the tide and the state of the breakers on the port pass, port commanders are instructed to temporarily interrupt the departures of speedboats to Nusa Penida. Passengers are urged to check the status of connections with their airlines before traveling to the port of Sanur.

Red flags on beaches and safety instructions

On the Balinese coast, the Badung lifeguard corps (Balawista) and the Pecalang customary police raised the red flag on the exposed beaches of the southwest:

1. Swimming strictly prohibited: Total ban on entering the water on the beaches of Uluwatu, Padang Padang, Echo Beach (Canggu) and Tanah Lot due to violent rip currents.
2. Extreme danger on the rocky flats: It is strictly forbidden to approach the edge of the cliffs and natural pools of Devil's Tear in Nusa Lembongan and Angel's Billabong in Nusa Penida, where sudden sea waves can mow down walkers.
3. Emergency number: In the event of an incident at sea or on the beaches, the national rescue service (Basarnas Bali) can be reached 24 hours a day on the emergency number 115 or on marine VHF channel 16.