Best weather for scuba diving in Southeast Asia — season-by-season guide
When to dive in Thailand, Indonesia, Philippines, Malaysia and Myanmar. Visibility, currents, water temperature and manta ray seasons by destination.
Overview
Southeast Asia has some of the world's best diving — from the coral triangle of Indonesia and the Philippines to the whale sharks of Myanmar's Mergui Archipelago. Dive conditions vary dramatically by season because visibility, currents and marine life migrations all follow the monsoon cycle. Choosing the right season for each destination can mean the difference between 30-metre visibility and 5-metre murk.
Thailand
Andaman Sea (Similan Islands, Richelieu Rock, Hin Daeng): Best November to April. Peak visibility and manta rays in February-March. Similans close May-October due to rough seas. Gulf of Thailand (Koh Tao, Sail Rock, Chumphon Pinnacle): Best March to September. Whale sharks appear at Sail Rock from March to May. The Gulf is diveable year-round but October-December has reduced visibility from monsoon runoff.
Indonesia
Raja Ampat: Best October to April for calm seas and manta rays. Water temperature 28-30°C year-round. Komodo: Best April to September for manta rays at Manta Point and best visibility. Bali (Tulamben, Nusa Penida): Manta season at Nusa Penida peaks July to November. Mola mola (ocean sunfish) appear July to October. Sulawesi (Bunaken, Lembeh): Diveable year-round, best visibility March to October.
Philippines
Tubbataha Reef: Only accessible March to June due to rough seas the rest of the year. One of the world's best dive sites. Malapascua (Cebu): Thresher sharks year-round, best conditions February to May. Apo Reef: Best January to May. Coron: Best October to May for wreck diving. Siargao: Limited diving infrastructure but improving; best February to May.
Malaysia
Sipadan (Sabah): Diveable year-round but best April to December. Permits are limited to 120 divers per day. Perhentian and Redang: Only diveable April to October — islands close November to March. Layang-Layang: Hammerhead season April to May. Mabul and Kapalai: Year-round muck diving, best visibility April to September.
Water temperature guide
Southeast Asian dive waters are consistently warm: 27-30°C throughout the year. A 3mm shorty wetsuit is sufficient for most sites. Thermoclines can drop temperatures to 22-24°C in deeper water, especially in currents (Komodo, Nusa Penida). Indonesia's upwelling zones occasionally bring 20°C water — a 5mm suit is recommended for deep diving at these sites.
Frequently Asked Questions
What is the best overall month for diving in Southeast Asia? ▾
April — it falls within the optimal window for most major dive destinations: Similans are still open, Komodo visibility is good, Philippines is dry, and Raja Ampat has calm seas.
Do I need a wetsuit for diving in Southeast Asia? ▾
A 3mm shorty is recommended even though water is warm (27-30°C). Multiple dives per day, deeper profiles and upwelling currents can make thinner exposure protection uncomfortable.