Diving in Thailand in March

Conditions in March

So, you're eyeing Thailand for a dive trip in March? Excellent choice! This month typically falls within the sweet spot of the dry season for the Andaman Sea, which is where the vast majority of Thailand's premier dive sites are located. Expect blissful conditions that are the stuff of diver dreams. The weather topside is generally sunny and warm, with minimal rainfall. The sea state is usually calm and flat, making for super comfortable liveaboard journeys and relaxed entries and exits from the water. You’ll be treated to crystal-clear visibility, often ranging from an impressive 20 to 40 meters, especially around the Similan and Surin Islands. Water temperatures are wonderfully consistent and warm, hovering around 28-29°C (82-84°F). This means you can comfortably dive in a thin wetsuit or even just a rash guard, though we’ll get into that more later. While currents at some sites can be moderate to strong, particularly around pinnacles and channels, March usually offers a good balance, providing drift diving opportunities without being overwhelmingly challenging for experienced divers.

The Gulf of Thailand, on the eastern side, offers a different, though still enjoyable, experience in March. While less famous for pelagics than the Andaman, conditions are also generally very good. Water temperatures mirror those of the Andaman, staying around 28-29°C (82-84°F) and visibility typically ranges from 10 to 25 meters. The sea state is usually calm, making for easy diving. While the Andaman Sea is definitely the star during March, don't dismiss the Gulf if your itinerary keeps you closer to those shores. However, for that truly iconic Thai diving experience with the big stuff, the Andaman is where you’ll want to be.

What you will see

March is absolutely prime time for pelagic encounters in the Andaman Sea. This is a fantastic month for whale shark sightings, especially around the Similan and Surin Islands, with Richelieu Rock being one of the most famous hunting grounds for these gentle giants. While nothing in nature is guaranteed, your chances are significantly boosted in March. You'll also have excellent opportunities to spot majestic manta rays gliding gracefully, particularly around Koh Bon and Hin Daeng/Hin Muang. These sites are renowned for their cleaning stations and provide spectacular interactions. Beyond the megafauna, you’ll regularly encounter leopard sharks resting on sandy bottoms, blacktip reef sharks patrolling the reefs, and sometimes even grey reef sharks.

The vibrant coral reefs themselves are teeming with life. Keep your eyes peeled for schools of barracuda, trevally, and snappers. Moray eels of various species, including giant morays, honeycomb morays, and white-eyed morays, peek out from their rocky hideaways. For macro lovers, a keen eye will reveal an astonishing array of critters: flamboyant cuttlefish, intricate nudibranchs in every color imaginable, ghost pipefish, and various species of shrimp and crab tucked away in crevices. The sheer biodiversity in places like the Similan and Surin Islands is breathtaking, making every dive a treasure hunt. Don't be surprised to find yourself mesmerized by the sheer volume of reef fish, from colourful parrotfish and angelfish to inquisitive clownfish defending their anemone homes.

Top dive sites this month

Hands down, the Similan Islands and Surin Islands, accessible by liveaboard from Khao Lak, are the absolute must-do destinations in March. Within this region, Richelieu Rock is legendary and often cited as one of the best dive sites in Thailand, if not the world. Its horseshoe-shaped pinnacle rises from the depths, covered in soft corals and bursting with life, making it a magnet for whale sharks, barracudas, and an incredible array of macro creatures. Another gem is Koh Bon, famous for its manta ray cleaning station, where these magnificent creatures often put on a spectacular show.

Further south in the Andaman Sea, Hin Daeng and Hin Muang are two submerged pinnacles renowned for their dense soft corals and being another hotspot for manta rays and occasional whale shark sightings. The currents here can be stronger, but the rewards are immense. For those looking for slightly calmer waters but still fantastic diving, the dive sites around Koh Lanta offer beautiful coral gardens and a good chance to see leopard sharks. While March is fantastic across the Andaman, focusing your trip on a liveaboard covering the Similan and Surin Islands, including Richelieu Rock, will give you the best possible chance for those bucket-list pelagic encounters.

Practical tips for your trip

Given the balmy water temperatures of 28-29°C (82-84°F), you’ll be perfectly comfortable in a 3mm shorty wetsuit, or even just a rash guard for most dives. Some divers prefer a full 3mm suit for sun protection and added warmth on multiple dives, but anything thicker will likely be overkill. March is generally suitable for all levels of divers. While some sites like Hin Daeng and Hin Muang can have stronger currents, a good liveaboard operator will guide you to appropriate sites based on your experience. However, to truly enjoy the diversity of conditions and make the most of drift dives, being comfortable with moderate currents is a plus.

Liveaboard availability in March can be tight as it's peak season for the Andaman Sea. We highly recommend booking your liveaboard well in advance – think 6-12 months out – especially if you have specific dates or a particular boat in mind. Beyond your diving gear, pack light, breathable clothing for topside excursions. Don't forget reef-safe sunscreen, a wide-brimmed hat, and insect repellent. A decent underwater camera is also a must to capture the incredible marine life. Be aware that most liveaboards depart from Khao Lak or Phuket for the Similan/Surin region, so plan your international flights accordingly and allow for travel time to these departure points. Given the stable conditions, seasickness is rarely a major issue, but if you're prone to it, bring your preferred medication. Enjoy your incredible diving adventure in Thailand!