One of the best things about scuba diving in Southeast Asia is that somewhere in the region is always in season. While individual destinations have their peak months and monsoon seasons, the diversity of geography means you can find excellent diving conditions every month of the year if you know where to look.

Here is a month-by-month breakdown of the best time to dive across Southeast Asia’s top destinations, so you can plan your trip around optimal conditions.

Peak Season Thailand Andaman and Komodo Mantas

January and February

The Andaman Sea coast of Thailand (Similan Islands, Koh Lanta, Koh Phi Phi) is in peak dive season with calm seas, warm water, and visibility reaching 30 meters or more. This is prime time for the Similan Islands, with manta ray sightings common at Koh Bon and whale sharks occasionally appearing at Richelieu Rock.

In Indonesia, southern Komodo dive sites are alive with manta rays feeding on plankton-rich upwellings. Raja Ampat is also excellent during these months with calmer seas and warm water. The Philippines’ Visayas region (Moalboal, Malapascua) offers good conditions, and it is one of the best times for thresher shark encounters at Malapascua.

Tubbataha Season Opens

March and April

Thailand’s Andaman dive season continues strong through March, with April marking the tail end before monsoon season begins. The Similan Islands close for the season in mid-May, so this is your last window.

Tubbataha Reefs in the Philippines opens for its short liveaboard season in March, offering pristine wilderness scuba diving through June. This is a bucket-list window you do not want to miss. Conditions across Indonesia remain excellent, with Komodo’s northern dive sites improving as the dry season begins.

Photo by Johnny Africa

Gulf of Thailand and Indonesia Dry Season

May and June

The transition period in Thailand as the southwest monsoon arrives on the Andaman coast. Gulf of Thailand destinations like Koh Tao and Koh Samui remain diveable and are entering their calmer months, making this a great time for scuba certification courses.

Indonesia’s dry season is underway. Komodo’s northern sites like Batu Bolong and Castle Rock are in peak form with excellent visibility. See our Komodo diving guide before you go. Bali diving, especially around Nusa Penida and Tulamben, is consistently good. Sipadan in Malaysia offers great dive conditions year-round.

Photo by Pascal van de Vendel

Mola Mola Season at Nusa Penida

July and August

Peak season for Bali’s Nusa Penida, where the famous mola mola (ocean sunfish) start appearing in the cooler upwellings. Manta Point also delivers reliable manta ray encounters. Read our Nusa Penida diving guide for the full site rundown. Koh Tao in Thailand is in great shape with calm waters and good visibility, ideal for PADI Open Water certification courses.

Komodo continues to offer excellent northern diving, and Sipadan’s conditions are strong. Raja Ampat enters a slightly rougher period but still offers world-class scuba diving.

Mola Mola Peak and Andaman Revival

September and October

Bali’s mola mola season peaks in September and October. Water temperatures around Nusa Penida can drop to 18-20°C in the thermocline where the sunfish appear, so bring a thicker wetsuit or hood.

Thailand’s Andaman coast begins to settle as the monsoon winds down in October, with the Similan Islands dive season restarting soon. Komodo’s northern dive sites remain excellent, and conditions across the Philippines are favorable.

Similan Season Returns and Raja Ampat Prime Time

November and December

The Similan Islands reopen for a new dive season, and Andaman coast scuba diving kicks back into gear. Early season sometimes brings whale shark sightings around Richelieu Rock. Komodo’s southern manta season begins as cooler water returns to Manta Alley.

Raja Ampat is entering one of its best periods with calm seas and excellent visibility. The Gulf of Thailand can get rougher in November with the northeast monsoon, though Koh Tao often remains diveable.

Photo by Jeremy Bishop

Southeast Asia Dive Season FAQ

When is the best time to dive in Southeast Asia?

There is no single best month, because somewhere in Southeast Asia is always in season. Thailand’s Andaman coast peaks from November to April, Indonesia’s dry season runs from May to October, and Raja Ampat is at its best from November to February.

When is mola mola season in Bali?

Mola mola appear at Nusa Penida from July, and sightings peak in September and October. Water in the thermocline can drop to 18-20°C, so bring a thick wetsuit.

When do the Similan Islands open?

The Similan Islands dive season runs from November to mid-May. The islands close for the monsoon for the rest of the year.

Where can you dive during the monsoon?

When the Andaman coast turns rough, the Gulf of Thailand around Koh Tao stays calm from May onward. Sipadan in Malaysia offers great conditions all year.

Plan Your Dive Trip with Scubalo

Knowing the best time to dive is half the equation. The other half is finding the right dive center at your chosen destination. Scubalo makes both easier by combining dive site information with verified operator listings, so you can match the season to the destination and the destination to a trusted dive center. Start planning with verified dive centers on Scubalo. Diving Indonesia specifically? Our region-by-region Indonesia season guide goes deeper.

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