Whale shark season: where and when to dive with them globally

The basics worth knowing first

Whale sharks are sharks, not whales. They’re filter feeders — sucking in seawater and straining out plankton, krill, and small fish through gill rakers. They are harmless to humans. They are not territorial, not aggressive, not interested in you. The risk in a whale-shark encounter is to the shark, not the swimmer — boat strikes and tourist contact damage their mucus layer.

International ethical guidelines, used by every reputable operator:

• Maintain at least 3 meters distance at all times
• No touching under any circumstances
• No flash photography — flashes are believed to stress the animal
• No blocking the path of a swimming animal
• Maximum 8-10 swimmers per shark in the water at once

Most “trips” are snorkeling, not scuba. The sharks feed near the surface and operators want maximum bottom time at depth where the action is. A few sites (Galapagos, parts of the Maldives) offer real scuba encounters at depth.

Site-by-site guide

Ningaloo Reef, Western Australia — March to July

The most consistent whale shark aggregation on Earth. The Ningaloo coast (around Exmouth and Coral Bay) sees daily sightings from late March through mid-July, with April-June being the peak.

Operators use spotter planes, which makes the encounter rate exceptional — roughly 85-95% of full-day trips see at least one shark, with multiple-shark days common. Tours run from Exmouth, leave around 8am, return around 4pm, with 3-5 in-water swims per trip.

Cost: AUD $400-500 (≈10,000-13,000 THB / $270-340) for a day trip.

The downside: Exmouth is remote. Closest commercial airport is Learmonth, served by 1-2 flights a day from Perth. Two-hour drive from Coral Bay. Worth the trip if you want the highest-probability encounter on the planet.

Donsol, Philippines — November to May (peak February-April)

Sorsogon province, southern Luzon. A community-managed sanctuary, no feeding allowed (a critical distinction from Oslob — see below). Boats find the sharks by spotter rather than baiting. Peak season is February through April with daily sightings; November-January and May are shoulder seasons with lower probability.

In-water encounter rate during peak: 70-85%. Boats run morning trips, 3-hour duration, typically 1-3 sharks per trip when conditions are right.

Cost: roughly $50-100 per person for a boat trip. Very affordable compared to Australia.

Oslob, Philippines — discussed honestly

Oslob, on the southern coast of Cebu, has year-round, near-100% encounter rates with whale sharks. Sounds great. The catch: the sharks are fed daily by local fishermen using small boats and buckets of small shrimp (uyap). The animals have become conditioned and stay in the area year-round to be fed.

The ethical case against Oslob is well-documented:

• Disrupts natural migration patterns (sharks that should be feeding across vast ocean areas instead loiter in a small bay)
• Risk of habituation reducing wild feeding skills
• High collision rates with boats due to crowding
• Tourists routinely violate the 3m rule (and operators do little to enforce it)

Most international conservation organizations (WWF, LAMAVE, MarineMegafauna Foundation) recommend not visiting Oslob and choosing Donsol instead, where the encounter is on the shark’s terms. The encounter rate at Donsol is lower in absolute numbers but ethically defensible.

If you’ve already been, you’ve already been. Going forward, Donsol is the better Philippines option.

Maldives, South Ari Atoll — November to April (year-round possible)

The Maldives is unusual: whale sharks are present year-round in the South Ari Marine Protected Area, with the highest densities November-April. The southern atolls (Addu, Foammulah) sometimes have shark aggregations in the southwest monsoon (May-October) when sharks move there.

Encounter probability on a dedicated South Ari liveaboard week: 50-70%. Day trips from Maamigili Island during peak season: 40-60%. Lower than Ningaloo because the area is much larger and spotter coverage is thinner.

What makes the Maldives different: many encounters are at depth, on scuba, rather than snorkel-only. The sharks here often cruise at 15-25m along reef walls. A good Maldives liveaboard pairs whale shark hunting with manta encounters at the cleaning stations.

Cost: liveaboard week $1,200-2,500. Day trips $150-300.

Mexico — Holbox, Cancun, Isla Mujeres — July to September

The Yucatán aggregation is one of the largest in the world. Hundreds of whale sharks gather in the warm waters off Holbox and Isla Mujeres in July, August, and early September to feed on tuna and bonito spawn.

Encounter probability in season: 90-95% — easily comparable to Ningaloo. The visual experience is different: dozens of sharks feeding vertically in a small area, often with manta rays mixed in. Snorkel-only, strict regulations, 2 swimmers per shark.

Cost: $150-250 day trip from Cancun or Isla Mujeres.

The catch: it’s a popular Caribbean tourist area, so crowding is real. Pick an operator certified by the Mexican government (CONANP) — they cap boat numbers.

Koh Tao and the Gulf of Thailand — March to May, occasional August-September

Koh Tao gets whale sharks. It does not get them reliably. Sightings cluster around March-May (warmer water, plankton blooms at Chumphon Pinnacle and Sail Rock) and a smaller spike in August-September. Outside those windows, encounters are rare-but-possible.

Honest probability of seeing one on a 4-dive Koh Tao trip during peak season: 10-25%. During the rest of the year: 2-5%.

The good news: when they come, the visibility is often excellent and the sharks are typically curious rather than skittish. The bad news: you can’t plan a Koh Tao trip for whale sharks. Plan for the diving and the certifications, and treat a whale shark as a bonus.

Mafia Island, Tanzania — October to March

Mafia Island (south of Zanzibar) hosts a whale shark feeding aggregation off Kilindoni beach. Peak season November-February. The sharks feed on surface plankton, encounters are snorkel-only, and the probability in peak is 80-90%.

Cost: $50-80 boat trip locally. Reaching Mafia is the harder problem — flights from Dar es Salaam.

Galapagos, Ecuador — June to November

Different style of encounter. The Galapagos whale sharks are mostly large pregnant females — animals that don’t appear at other aggregation sites. Sightings are at depth (10-30m) on scuba, on liveaboards visiting Darwin and Wolf islands. Peak is July-October.

Encounter probability on a Galapagos liveaboard in season: 60-80%, but with the caveat that this is advanced diving — strong currents, surge, depth. Not for new divers.

Cost: Galapagos liveaboard week $4,500-7,000. The most expensive whale shark encounter on this list, justified by the rest of the diving (hammerheads, marine iguanas, Galapagos sharks, mola mola).

Mozambique, Tofo — October to March

Praia do Tofo, on Mozambique’s south coast, is a year-round whale shark site with peak density October through March. Encounter rate in peak: 60-75%.

Tofo is also globally important for manta research (the Marine Megafauna Foundation is based there). Combining whale sharks with mantas in one trip is a strong reason to pick this site.

Cost: $80-150 day trip. Reaching Tofo means flying into Inhambane or driving from Maputo.

Utila, Honduras — March-April and August-October

The Bay Islands aggregation runs in two pulses linked to plankton blooms — late March to April, and August through October. Encounter rate during peak windows: 40-60%. Utila has the cheapest Caribbean dive scene and the whale shark trips are reasonably priced.

Sodwana Bay, South Africa — November to March

KwaZulu-Natal coast aggregation. Summer-season (Southern Hemisphere) sightings, peak December-February. Encounter rate around 40-60% during peak.

Encounter probability by site, in season

These are rough averages from operator reports and citizen-science databases (Wildbook for Whale Sharks aggregates global sighting data). Year-to-year variation is significant — bad plankton year, low encounters everywhere.

Snorkel or scuba?

By international rule and most national regulations: most whale shark encounters are by snorkel. Reasons:

• Sharks feed near the surface, so depth diving misses them
• Bubble noise from scuba can spook the animals
• Surface encounter lets more guests in the water per shark

Sites where scuba encounters are normal: Galapagos (depth diving on liveaboard), parts of the Maldives (chance encounter at reef-wall depth), occasional encounters during normal dives at Koh Tao or Komodo.

If your dream is scuba-only encounters, Galapagos is the destination. For everywhere else, accept that you’ll be snorkeling.

How to behave in the water

The Code of Conduct adopted by most operators:

1. Stay 3m from the body, 4m from the tail. A whale shark’s tail is powerful and can knock a swimmer hard if you’re behind it.
2. No touching, ever. Their skin has a protective mucus layer that human contact damages.
3. No flash, no strobes. Use natural light for photos.
4. Don’t chase. If the shark turns away, let it. Don’t kick after it.
5. No diving beneath. Stay above or to the side, never directly under.
6. Max 8-10 swimmers per shark, max 30 minutes in the water with one animal (rules vary by site).

Good operators enforce these. Bad operators don’t. Choosing a certified, conservation-aligned operator is the single biggest ethical decision you’ll make.

What if you don’t see one

Pre-book sites where the operator offers a second trip free or at low cost if no sightings. Common policy at:

• Ningaloo operators (most offer 50% second-trip discount)
• Donsol BIO-managed boats (free second attempt if shark not seen)
• Holbox and Isla Mujeres operators (often “guarantee” policies in peak season)

Liveaboards generally don’t guarantee — you’re already paying for a week and the schedule covers many other sites. Day-trip operators are where the guarantee policies live.

Recommended specialist operators

A non-exhaustive list of operators with strong reputations for whale shark trips:

• Ningaloo Whaleshark Swim and Three Islands Whale Shark Dive in Exmouth
• Bicol Dive Center and BIO (Butanding Interaction Officers) in Donsol
• LAMAVE (research-led) for Philippines field experiences
• Whale Shark Dive Maldives and various South Ari liveaboards (Carpe Diem, Emperor)
• Solo Buceo and Ceviche Tours in Holbox
• Marine Megafauna Foundation for citizen-science participation in Tofo, Mozambique

Pick by what you actually want

• Highest probability single-trip experience: Ningaloo (April-June) or Holbox (August)
• Best combination of whale shark + other megafauna: Galapagos (July-October) or Tofo (November-February)
• Ethical experience on a tight budget: Donsol, Philippines (February-April)
• Year-round option from somewhere convenient: Maldives liveaboard (November-April)
• As a bonus during normal recreational diving: Maldives, Komodo, southern Bali, Koh Tao March-May

Plan around the season. Book a flexible-date trip if you can. And accept that a whale shark encounter is fundamentally on the animal’s terms — even at Ningaloo, sometimes the ocean just doesn’t deliver.