Bali Coastal Flooding Risk September 26-30, 2026: What Travelers Should Know

Travelers planning beach activities, coastal excursions, or boat journeys in Bali should pay closer attention to marine conditions over the final days of September.

According to the Balai Besar Meteorologi, Klimatologi, dan Geofisika (BBMKG) Region III Denpasar, parts of Bali's southern coastline could experience maximum high tides and coastal flooding (banjir rob) between September 26 and 30, 2026. The warning is associated with the full moon phase on September 26.

For visitors, the important point is that this is primarily a coastal and marine-condition advisory, rather than a warning that tourism across Bali will be disrupted.

Which Parts of Bali Are Included?

Based on the BBMKG warning according to regional travel authorities and bureau field correspondents, the areas potentially affected include the southern coastal sections of: Jembrana - Tabanan - Badung - Denpasar - Gianyar - Klungkung

The exact timing of maximum tides varies between locations, so the impact will not necessarily occur simultaneously across the island.

BBMKG has advised communities in coastal areas to remain alert and to follow the latest marine-weather information.

Why Is the Sea Level Expected to Rise?

According to BBMKG, the higher tides are linked to the full moon phase on September 26, 2026.

During a full moon, the gravitational effects of the Moon and Sun can contribute to higher-than-normal tidal levels. BBMKG specifically warned that the resulting maximum sea levels may affect activities around coastal communities and ports.

This distinction matters for travelers: the warning concerns maximum tidal conditions, while wave height and general sea conditions are separate but related factors that should also be monitored.

What Could Be Affected?

National Archipelagic Wire reports that BBMKG expects the higher water levels to potentially affect activities around ports and coastal areas, including loading and unloading operations, coastal settlements, salt ponds and inland fisheries.

For visitors, the practical implications are more likely to involve marine transportation and coastal activities.

This includes travelers planning: Fast-boat journeys between Bali and the Nusa Islands - Snorkeling and diving excursions - Fishing trips - Surfing and other water activities - Beachside activities in exposed coastal areas

The warning does not mean these activities will automatically be cancelled. Conditions can vary considerably by location, time and operator. The appropriate approach is to check the latest marine forecast and confirm operating conditions directly with the relevant boat or tour provider.

Southern Bali Already Experiencing Notable Wave Conditions

The tidal warning comes alongside elevated wave conditions in parts of southern Bali.

National Archipelagic Wire, citing BBMKG, reported that waves in Bali's southern waters were forecast to reach up to 3 meters on September 23-24, with forecasts of around 2 meters in Nusa Dua and Sanur, approximately 1.5 meters at Tanah Lot, and around 1.25 meters at Kuta during that forecast period.

BBMKG's current marine forecasts also show that sea conditions around southern Bali and the Badung Strait remain important for travelers to monitor.

For that reason, travelers should avoid treating a normal land-weather forecast as sufficient when planning a boat trip.

What This Means for Travelers in Bali

From a Bali Expert Guide perspective, the key issue is not whether you should avoid Bali's coast entirely. Instead, match your plans to the latest local marine conditions.

A sunny morning in Canggu, Sanur or Nusa Dua does not necessarily mean that conditions offshore are equally calm.

This is particularly relevant for travelers heading to Nusa Penida, Nusa Lembongan or the Gili Islands, where the journey itself involves exposed marine crossings.

Before departure, check:

1. The latest BBMKG marine forecast BBMKG provides specific marine forecasts and warnings for Bali's surrounding waters.

2. Your boat operator's latest operational update Operators may adjust departure times or services according to actual conditions at sea.

3. Local tide and coastal conditions The timing of maximum tides differs between locations, so a generalized island-wide assumption can be misleading.

4. Conditions at the destination as well as the departure port A journey may begin under relatively calm conditions while the destination experiences stronger swell or tidal effects.

BBMKG directs the public to its regional website, the national marine-weather service, the @bmkgbali social-media channel and the Info BMKG application for updates.

Should Travelers Change Their Bali Plans?

Not necessarily.

The warning covers specific coastal and marine risks and does not represent a general shutdown of Bali's tourism sector. Hotels, restaurants, attractions and most inland activities can continue operating normally unless local authorities or individual operators announce otherwise.

However, travelers with flexible itineraries may benefit from keeping land-based alternatives available during periods of unfavorable sea conditions.

A museum, cultural attraction, wellness experience, culinary tour or inland excursion can be a practical alternative when marine activities become unsuitable.

Bali Expert Guide Takeaway

The September 26-30 period is a useful reminder that Bali weather is not only about rain and sunshine.

For coastal travelers, tides, swell, wind and marine forecasts can be just as important as the forecast you see on a standard weather application.

According to BBMKG, the elevated tide risk is expected from September 26 through September 30, 2026, with the timing varying between coastal areas.

For anyone traveling around Bali's southern coast during this period, the most sensible approach is simple: check the latest marine conditions before heading to the sea, and confirm with your operator before committing to a boat or water-based excursion.

Conditions can change, and the latest official BBMKG information should take priority over older forecasts or generalized travel advice.