Saleh Bay whale shark season: year-round sharks, disputed peak months

By Saleh Bay Whale Shark Editorial Desk

There is no agreed Saleh Bay whale shark season. A 2017 to 2022 record logs sharks year-round with most observations in March and April, fishers have named June, and one operator says August and September. Those peaks may be measuring different things, so choose dates by sea conditions, crowding and spare mornings rather than by one month.

Three questions get folded into the phrase "best time to see whale sharks in Saleh Bay", and they have different answers:

• Presence: are sharks using the bay at that time of year? Research sources say yes, in every season.
• Observation peak: when were the most sharks recorded or remembered? Here the sources split.
• Comfort: when do boats cross with the least trouble and the least company? That is mostly an operator's judgement, and operators do not fully agree either.

Is there really a Saleh Bay whale shark season?

Not in the sense of an arrival and a departure. The IUCN shark specialist group factsheet for Saleh Bay, the largest bay on Sumbawa according to Wikipedia, reports observations in all parts of the year across 2017 to 2022. A 2026 satellite tracking paper in Frontiers names Saleh Bay and Cenderawasih Bay as the persistent year-round habitats among the Indonesian sites it studied. A 2025 Frontiers paper draws the contrast with Talisayan, where aggregations are seasonal, and with Probolinggo, where they are not tied to bagans, the lift-net fishing platforms that sharks visit here.

The same tracking paper adds a qualifier that buyers rarely see. Individual residency is variable and generally short. "Year-round" therefore describes the bay as a place where some sharks tend to be present, not a resident group waiting for you in any given week. The resort Amanwana says the sharks can be seen all year and also says sightings cannot be guaranteed, and that pairing is the right way to hold both ideas.

Two small records show what presence looks like on the water. Of 11 research trips logged in a 2021 study between November 2019 and January 2020, eight met whale sharks and three did not. That is a tiny sample from a wet-season transition, so it is not a sighting rate. Kompas quotes an operator saying one point usually holds one to five sharks a day and at least one, and Kompas describes the figure as tentative. Our page on whether Saleh Bay sightings can be counted on goes further into those numbers, and the Saleh Bay whale sharks overview covers how the counts have grown.

Which months do sources call the peak?

This table lists each claim beside the kind of source making it. Read the last column first, because it explains most of the disagreement.

The factsheet, the fishers quoted in a research paper on the bay and Ocean Earth Travels make three different peak claims. This guide does not pick a winner, because nothing published here tests them against each other on the same terms. The planning windows from SB Excursions, The Langkah Travel and My Best Places to Visit overlap, yet they answer a question about boats rather than sharks.

Why might those peaks disagree?

Observation totals can rise with survey effort: more observers in March and April would produce more records in those months whether or not more sharks arrived. Fisher recollections reflect what crews noticed at their own platforms in the years they were asked. An operator's peak presumably comes from its own departures, and the months with the most boats out also have the most people looking.

The platforms move as well. Fishermen interviewed for the 2021 study said bagans work their way west across the bay when the wet western season brings rain and strong winds, seeking shelter around islands. A count from one area can therefore change because the fishing fleet relocated. That same study also recorded 39 sharks between November 2019 and January 2020, sized 2.5 to 7 metres, in months that none of the three peak claims mention.

Time of day may matter more than the calendar. The study reports sharks around bagans from about 05:00 to 09:00, and then not seen there. The factsheet has them taking krill and small pelagic fish in the mornings, then moving vertically, presumably to feed on sergestid shrimps in the afternoon. For a bagan-based morning, arriving late could cost you more than choosing the "wrong" month.

Do calm seas line up with the peak months?

Not neatly. The factsheet pairs December to February, the northwest monsoon, with light winds and heavy rain, and June to August, the southeast monsoon, with strong winds and less rain. SB Excursions, meanwhile, calls April to October the calmest span with the fewest cancellations. Those two descriptions sit awkwardly together, since the strongest winds in the factsheet fall inside the operator's comfortable months, and the operator calls January and February the roughest when the factsheet lists low wind speeds there. Monsoon averages and a boat crew's experience of chop are not the same measurement, and the bay's shelter varies by location. See our Saleh Bay weather guide before you settle on dates, then check a current forecast nearer the time.

Does the moon phase matter?

It might, though no source gives data. Amanwana favours the new moon, when it says the sharks tend to be easiest to see and most active. The Langkah Travel says older guides avoided the full moon, and that more fishermen now keep bagans running through the lunar cycle. Peter Orsel, a travel blogger, reports the reverse: that around the full moon fishermen do not operate, because bright moonlight makes their nets less effective, so sharks are less likely to appear. These accounts conflict. If your dates are flexible, ask a seller whether bagans in its area are fishing that week. Do not move a whole trip around it.

Which months are busiest at the bagans?

Ocean Earth Travels names July and August, and warns that several boats can gather around a single active bagan in the dry season. That is one company's account, and we know of no published monthly visitor count for the bay. Note that its two busiest months overlap its own August and September sighting peak, so the time it rates highly for sharks is also when you are likely to share them. For that reason the same operator suggests May, June, September or October. If you are weighing a crowded month, our Saleh Bay whale shark tour checklist has questions on boat limits, the Saleh Bay whale shark cost guide shows what a spare morning adds, and swimming with whale sharks at Saleh Bay describes the morning itself.

How should you choose your dates?

Start from your constraints, then use the claims above to break ties:

• Fixed holiday dates: check the sea-condition claims for your month. A second morning gives another attempt, though no source measures how much that helps.
• Fewer boats matter most: ask about May, June, September and October, the months one operator suggests, and ask how many boats it saw last week.
• A nervous sailor in the group: weigh the April to October advice against the windier June to August monsoon, and ask where the active platforms are, since a shorter crossing may help more than the month.
• December to April: one blog reports tours running on most days with cancellations possible, so add a spare day before any onward flight.

What do travellers ask about the timing of a trip?

Are whale sharks in Saleh Bay all year?

Research sources describe the bay as a year-round habitat, though individual sharks tend not to stay long. Presence across the year is not a promise for one morning, and some trips still come back without a sighting.

What is the best month for Saleh Bay whale sharks?

No month can fairly be named. March and April, June, and August and September each have a source behind them, and those sources measure different things. Sea conditions, crowding and spare mornings are firmer grounds for choosing.

Does the moon phase affect Saleh Bay whale shark sightings?

Possibly, but no source gives data. A resort favours the new moon, one operator says bagans now work through the full moon more often than they once did, and a travel blogger says they stop around it.

Which months are busiest at Saleh Bay?

One operator names July and August. We know of no published monthly count, so treat that as a single company's experience rather than a measured figure.

Why do sources disagree about the Saleh Bay whale shark peak?

Research totals depend partly on survey effort, fisher recollections cover particular years, and sellers speak from their own trips. Bagans also relocate around the bay with the weather, which can shift where sharks get counted.

Which sources support this page?

• IUCN shark specialist group: Saleh Bay Important Shark and Ray Area factsheet
• Wikipedia: Saleh Bay
• Frontiers in Marine Science 2026: whale shark satellite tracking in Indonesia
• Frontiers in Marine Science 2025: Indonesian whale shark aggregations compared
• Amanwana, resort: whale shark excursion
• 2021 study of whale sharks around Saleh Bay bagans (IOP Conference Series)
• Kompas: whale shark tourism in Saleh Bay, Sumbawa
• Study with fisher interviews on Saleh Bay whale sharks (IOP Conference Series)
• Ocean Earth Travels, operator: Saleh Bay whale shark guide
• SB Excursions, operator: whale shark season in Sumbawa
• The Langkah Travel, operator: Saleh Bay whale shark guide
• My Best Places to Visit, travel blog: whale sharks in Saleh Bay
• Peter Orsel: swimming with whale sharks in Sumbawa (travel blog)

How do I reach the desk?

Send your travel window and how many spare mornings you can allow. The desk replies with what it can source for those dates, and nothing is held for you until a written offer says so. A request can lead to a paid booking, so the desk has a commercial interest; our about page explains it.

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• Email: bd@juaraholding.com