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.

January and February:
Peak Season Thailand Andaman and Komodo Mantas

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.

March and April: Tubbataha Season Opens

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 generally excellent, with Komodo's northern dive sites improving as the dry season begins.

May and June:
Gulf of Thailand and Indonesia Dry Season

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. Bali diving, especially around Nusa Penida and Tulamben, is consistently good. Sipadan in Malaysia offers great dive conditions year-round.

July and August:
Mola Mola Season at Nusa Penida

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. 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.

September and October:
Mola Mola Peak and Andaman Revival

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 a thicker wetsuit or hood is advisable for scuba divers.

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 generally favorable.

November and December:
Similan Season Returns and Raja Ampat Prime Time

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.

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 at scubalo.com.