Best Time to Dive in Southeast Asia (2026 Diving Calendar)

Southeast Asia sits at the heart of the Coral Triangle, the richest marine region on Earth, and you can dive somewhere in it every month of the year. The catch is that “somewhere” moves with the seasons. Time a trip well and you get glassy water, big-animal encounters, and 30-metre visibility; time it poorly and you arrive to closed parks, rough crossings, and plankton soup. This guide maps out where and when to dive across Indonesia, Malaysia, the Philippines, Thailand, and Brunei, so you can match a destination to the right month.

Diving seasons in this part of the world are governed by a few forces working together:

• Monsoons. Two opposing wind systems — the southwest monsoon (roughly May to October) and the northeast monsoon (roughly November to March) — dictate which coasts are calm and which are stormy. Because they hit different regions at different times, the region as a whole is never fully “closed.”
• Visibility. Rain and wind stir up sediment and trigger plankton blooms, dropping visibility. The dry, calm side of each monsoon is when the water turns clear.
• Marine-life migrations. Some of the best encounters are seasonal: mola mola rise into Bali’s reefs on cold upwellings in the dry months, manta rays gather in Raja Ampat and Komodo when plankton is thick, and whale sharks follow their own regional calendars.
• Currents. The same currents that make sites like Komodo and Nusa Penida thrilling also make them advanced. Current strength shifts with the tides and the season, which affects both the diving and the marine life it attracts.
• Water temperature. Most of the region stays a warm 27–30°C year-round, but cold upwellings (Nusa Penida in mola season, southern Komodo) can drop water into the low 20s and bring thermoclines — worth a thicker wetsuit.

Southeast Asia at a Glance

Use this overview to narrow down a region, then read the country sections below for the detail. All tables scroll sideways on mobile.

Dive Season Calendar (Month by Month)

The tables below turn the whole region into one scannable view. Pick a month, read down the column, and see which sites are in their prime, which are diveable with some compromise, and which are shut for the monsoon. These windows are indicative — currents, plankton blooms, and weather shift from year to year — so confirm current conditions with a local operator before you commit to dates.

🟢 Prime — settled seas, best visibility, most marine-life activity · 🟡 Diveable — conditions vary, but still worth diving · 🔴 Closed — monsoon-affected and not recommended; some parks are legally shut.

Indonesia

Thailand

Philippines

Malaysia

Brunei

A few planning notes fall straight out of the calendar. Sipadan’s reefs dive well all year, but the island itself closes to divers every November for reef recovery, so base yourself on Mabul or Kapalai and earn Sipadan days by permit. Tubbataha and the Banda Sea are liveaboard-only and open for only a short season — Tubbataha roughly mid-March to mid-June, the Banda Sea across two brief windows. And Thailand’s two coasts run on opposite clocks: when the Andaman shuts for the southwest monsoon (the Similan Islands National Park is legally closed 16 May to 14 October), the Gulf around Koh Tao keeps going.

Entry requirements vary by nationality and change frequently, so always confirm before booking. As a 2026 snapshot for holders of a Chinese passport: Indonesia grants a visa on arrival or e-VOA; Thailand is visa-free for 60 days; Malaysia is visa-free for 30 days; and the Philippines is visa-free for 14 days with a valid onward or return ticket; and Brunei is visa-free for 14 days.

Indonesia

Indonesia is the most biodiverse dive destination on the planet, and it is really several dive regions in one country, each with its own season. Northern and eastern areas like Raja Ampat dive best in the northwest-monsoon “dry” window of October to April, while southern areas like Bali and Komodo peak during the southeast-monsoon dry season of roughly April to November.

Indonesia rewards every kind of diver. Wide-angle photographers head to Raja Ampat and Komodo for mantas, schooling fish, and reefscapes that fill a fisheye; macro shooters lose themselves in Lembeh and Ambon, where a single muck dive can turn up a dozen species you have never seen. Big-animal divers get manta cleaning stations, reef sharks, and the occasional hammerhead in the Banda Sea, while beginners can build confidence on the gentle shore dives of Tulamben and Bali, where the USAT Liberty wreck sits a short swim off a black-sand beach, and more advanced divers head to Nusa Penida for year-round mantas and seasonal mola mola. The trade-off is logistics: the best of Raja Ampat, the Banda Sea, and remote Komodo is reached by liveaboard, and travel between regions means domestic flights. For a gentler pace, Wakatobi and Derawan trade adrenaline for pristine, easy reefs — Derawan even has a lake full of harmless stingless jellyfish — while the Banda Sea’s remote seamounts reward experienced divers with schooling hammerheads and, in season, dramatic fish spawning aggregations. Read the full Indonesia diving guide for the region-by-region breakdown.

Malaysia

Malaysia splits neatly into two dive worlds. The peninsular east-coast islands sit in the South China Sea and close during the northeast monsoon (roughly November to February), diving best from March to October. Malaysian Borneo — Sabah, home to legendary Sipadan — sits in the Celebes Sea and dives well year-round.

Sipadan is the headline: an oceanic pinnacle where turtles are so common you stop counting, barracuda swirl in tornadoes at Barracuda Point, and grey reef sharks patrol the wall. Because it is strictly protected, you cannot just show up — Sabah Parks issues a limited daily permit only through licensed operators, so you book a package on Mabul or Kapalai and earn Sipadan days by rotation, which is why longer stays matter. Around it, Mabul and Kapalai are muck-diving gems in their own right. Over on the peninsula, the Perhentians and Tioman are among the cheapest, gentlest places in the region to learn, provided you come in the March-to-October window. Photographers should budget extra days on Mabul, where the muck sites turn up mandarinfish, flamboyant cuttlefish, and blue-ringed octopus after dark. Planning is mostly a matter of picking the right half of the country for your dates. Read the full Malaysia diving guide for the Sipadan permit system and both coasts.

Philippines

The Philippines runs on the northeast monsoon, locally called the Amihan: from roughly November to May the eastern seaboard is dry, calm, and clear, which is the prime dive window for most of the country. The southwest monsoon (Habagat, June to October) brings the wet season, though sheltered sites still dive well.

The Philippines is a macro photographer’s dream — Anilao and Dauin rival anywhere on Earth for critters, and Anilao has become a blackwater-diving hotspot. It is also a shark and pelagic destination: Malapascua offers the world’s most reliable daily thresher-shark encounters, and remote Tubbataha, reachable only by liveaboard in a three-month window, is arguably the finest reef in the country. Whale sharks feature too — the resident sharks at Oslob are seen year-round, while Donsol offers a more natural, seasonal encounter from about November to June. Beginners will find warm, easy diving around Bohol and Moalboal. Advanced divers can add the current-swept pinnacles of Verde Island off Puerto Galera and the remote reef walls of Apo Reef, both thick with fish. Read the full Philippines diving guide for every region in detail.

Thailand

Thailand has two coasts on two different monsoon clocks. The Andaman coast in the west — the Similan Islands, Phuket, Phi Phi, Krabi, and far-south Koh Lipe — dives best from November to April. The Gulf of Thailand in the east — Koh Tao, Koh Samui — is more forgiving, diveable most of the year and best from about February to September, with the wettest weather late in the year.

Thailand is where a huge share of the world’s divers earn their first certification, thanks to Koh Tao’s low prices and calm, shallow reefs. But it also has genuine world-class diving: the Similan Islands, dived mostly by liveaboard, deliver granite boulder scenery and the region’s best big-animal site at Richelieu Rock, where mantas and whale sharks appear from February to April. The key planning fact is the Similan closure — the national park shuts from 16 May to 14 October each year for the monsoon and reef recovery, so an Andaman trip must fall in the open season. If you are travelling in the low season, switch to the Gulf, where Koh Tao and Sail Rock keep diving. In the Gulf, Sail Rock off Koh Samui and Koh Tao is the signature site — a pinnacle with a vertical swim-through chimney that draws whale sharks in the warmer months. Pick your coast to match your travel dates and you will rarely be disappointed. Read the full Thailand diving guide for both coasts by season.

Brunei

Brunei is the region’s odd one out, and its quiet secret. The tiny, oil-rich sultanate on the north coast of Borneo has left its waters scattered with shipwrecks and old oil-rig structures, dived by a single operator with almost no other divers around. The water runs green and visibility is only ever average, but the wrecks are wrapped in fish. The season runs March to September, with the clearest water in May and June, and Advanced Open Water is the practical minimum everywhere here.

Brunei is for divers who value wrecks, macro, and empty water over clarity and big pelagics. Its own sites are Dolphin 88 (the friendliest to penetrate), the Bolkiah ferry, and the oil-rig reefs that have become a macro playground. The famous Big Four — the Cement, Blue Water, American, and Australian wrecks — are actually Labuan’s, lying across the bay in Malaysian waters; Brunei operators have long dived them, but access from the Brunei side is no longer guaranteed, so confirm before you count on them. Read the full Brunei diving guide for the wrecks, the single operator, and entry tips.

Best Destination by Interest

If you are planning around a specific experience rather than a country, start here. The picks below draw on the whole region, so a few sit outside the main tables above.

Month-by-Month Guide

A quick month-by-month view of where the diving is best, what is around, and what the weather is doing across the region.

January

Best destinations: Raja Ampat, Komodo, the Philippines (Anilao, Malapascua, Coron), and Thailand’s Andaman coast (Similan, Phi Phi). Marine life: manta aggregations in Raja Ampat and Komodo, thresher sharks at Malapascua. Weather: prime dry-season conditions across the Philippines, the Andaman, and Raja Ampat; peninsular Malaysia’s east coast is still in monsoon.

February

Best destinations: Raja Ampat, the Similan Islands (visibility at its best February to April), the Philippines, and Komodo. Marine life: mantas at their peak, and whale sharks starting to appear at Richelieu Rock. Weather: calm, dry, and clear across most of the region — one of the strongest all-round months.

March

Best destinations: the Similan Islands, the Philippines, Raja Ampat (late season), and — from mid-month — Tubbataha opens to liveaboards. Peninsular Malaysia begins reopening. Marine life: mantas and whale sharks at Richelieu Rock, pelagics returning to Tubbataha. Weather: dry on the Andaman and in the Philippines; the northeast monsoon easing off the Malaysian peninsula.

April

Best destinations: Tubbataha (peak begins), the Similan Islands (until mid-May), the Philippines, Raja Ampat (last calm month), and Malaysia’s Sipadan. Marine life: whale sharks and mantas at Tubbataha’s Delsan Wreck, plus Richelieu Rock. Weather: hot, dry, and calm; Indonesia’s south is transitioning toward its wet season.

May

Best destinations: Tubbataha (until mid-June), Malaysia (Sipadan and the reopened peninsular islands), the Gulf of Thailand, and Brunei (visibility at its best). The Similan park closes on 15 May. Marine life: pelagics at Tubbataha, macro across Malaysia. Weather: the southwest monsoon arrives on the Andaman coast, closing the Similans; the Gulf of Thailand comes into form.

June

Best destinations: Tubbataha (until mid-June), Malaysia (Sipadan, peninsular islands), the Gulf of Thailand (Koh Tao, Sail Rock), Bali, and Brunei (peak visibility for its wrecks). Marine life: whale sharks at Sail Rock, resident mantas at Nusa Penida. Weather: wet on the Andaman and in much of Indonesia; Malaysia and the Gulf of Thailand are in their stride.

July

Best destinations: Malaysia, Bali and Nusa Penida (mola mola season begins), Komodo, and the Gulf of Thailand. Raja Ampat enters its rough off-season. Marine life: mola mola on cold upwellings at Nusa Penida, mantas at Komodo. Weather: the southeast monsoon makes Raja Ampat and southern Misool rough, but southern Indonesia (Bali, Komodo) is dry and excellent.

August

Best destinations: Bali and Nusa Penida (mola mola peak in August and September), Komodo, Malaysia, and the Gulf of Thailand. Marine life: peak mola mola sightings at Crystal Bay, plus reliable mantas. Weather: the dry-season high point for southern Indonesia; Raja Ampat still windy; Malaysia settled.

September

Best destinations: Komodo, Bali and Nusa Penida (mola until October), Malaysia, the Banda Sea (liveaboard season begins), and Wakatobi. Marine life: mola mola, hammerheads in the Banda Sea, manta rays. Weather: dry in southern Indonesia; Raja Ampat calming late in the month; the Philippines’ wet season starting to ease.

October

Best destinations: Raja Ampat (season reopening as seas calm), Komodo, Bali, Malaysia, and — from 15 October — the Similan Islands reopen. Marine life: mantas returning to Raja Ampat’s cleaning stations, the tail of mola season in Bali. Weather: a transition month; the Andaman reopens, Raja Ampat settles, and the northeast monsoon begins in the Philippines.

November

Best destinations: Raja Ampat (building toward its peak), the Similan Islands (liveaboards running), and the Philippines (Anilao, Malapascua, Coron). Sipadan itself is closed all month for reef recovery — dive Mabul and Kapalai instead. Peninsular Malaysia’s east coast begins closing. Marine life: mantas in Raja Ampat, thresher sharks at Malapascua. Weather: dry and clear in the Philippines and on the Andaman; the northeast monsoon settling over peninsular Malaysia.

December

Best destinations: Raja Ampat (peak manta season, December to March), the Similan Islands, the Philippines (Coron, Anilao, Malapascua), and Komodo. Marine life: mantas across Raja Ampat and Komodo, thresher sharks, healthy reefs. Weather: dry and calm in the Philippines, the Andaman, and Raja Ampat; peninsular Malaysia’s east coast closed for the monsoon.

Planning Your Trip

There is no single best time to dive Southeast Asia — there is a best time for the dive you want. If your heart is set on manta rays and pristine reefs, aim for Raja Ampat between December and March. If you want mola mola, it has to be Bali from July to October. For a first open-water course, Koh Tao is calm and affordable most of the year, and for a bucket-list reef, Tubbataha’s narrow March-to-June window is worth planning a year ahead. Match the destination to the experience, then let the calendar tell you when to go.

A note on fees, permits, and access: several of the region’s headline sites are tightly controlled, and the rules and fees change often, so confirm current figures with your operator before booking. Sipadan in Malaysia is limited by a daily permit quota — raised to around 250 in 2025 — issued only through licensed operators, so you book a multi-night package on Mabul or Kapalai rather than buying a permit directly, and pay roughly MYR 450 a day in park and conservation fees; the island closes every November. Komodo in Indonesia shelved its controversial 2022 conservation fee, so day and park fees stay modest, but a new cap of about 1,000 visitors a day is rolling out for 2026, which makes the peak July-to-October dates harder to secure. Raja Ampat now charges two official fees totalling around IDR 1,000,000 — a marine-park entry tag valid for a year, plus a separate visitor ticket. Bali has charged every foreign visitor a one-off IDR 150,000 (about US$10) tourist levy since February 2024, paid through the Love Bali app. Tubbataha in the Philippines is liveaboard-only and open only from mid-March to mid-June, with a conservation fee of around PHP 5,000 (about US$90). And Thailand’s marine parks, including the Similans and Surin, charge foreigners about THB 500 per park plus a small daily diving fee, booked ahead through the national-park e-ticket system.

Whatever and wherever you shoot, water drains color fast with depth and distance, so your footage will need help afterward. It is worth understanding why underwater photos look blue and how to restore underwater photos before your trip; if you shoot an action camera, our guides to DJI Action and GoPro underwater color correction cover those systems, and the right underwater photo editor makes the edit quick once you are home. You can see the kind of color that is recoverable in our before-and-after gallery, and read more about our approach on the about page. For more guides on diving and underwater imaging, explore OceanDimana.