Whale shark season: Thailand sites and timing
The reality of whale shark sightings
Finding a whale shark is not guaranteed. I spent two weeks in Koh Tao back in 2018 and only saw one. Most divers see them for 10 to 20 seconds before they swim away. You might get a 5 minute interaction if the animal is feeding on plankton.
Luck plays a massive role. Statistics from local boat operators suggest a 1 in 10 chance during peak months. Do not plan your entire trip around a single sighting. It is better to focus on the marine life in general.
Expect some disappointment. Many people spend $150 USD on liveaboards and leave without seeing one. This is part of the ocean’s unpredictable nature.
Whale shark season Andaman side
The Andaman Sea offers the best opportunities. You should target the window between February and April. During this time, the currents around Richelieu Rock are very strong. These currents bring the food that attracts large pelagics.
Richelieu Rock is a pinnacle. It sits at a depth of roughly 15 m to 30 m. I remember seeing a 7 m long shark there in March 2021. The visibility was 25 m that day.
Hin Daeng is another key spot. It is located further south near the Burmese border. You need an experienced boat crew to handle the surge here. Most liveaboards depart from Phuket or Khao Lak.
If you choose a liveaboard, check the itinerary. Look for boats that visit the Similan Islands and Surin Islands. These routes offer the highest density of sightings.
Whale shark season Gulf side
The Gulf of Thailand follows a different schedule. You can find them near Sail Rock from March to May. This is a very popular time for divers in Koh Tao. The water temperature stays around 29 °C during these months.
There is also a second window. September and October often bring sightings near Chumphon. These months occur after the monsoon rains have settled. Many divers prefer this period because the crowds are smaller.
Koh Tao is famous for sightings. I saw a juvenile whale shark near Cham Chon in 2019. It was only about 3 m long. The water was quite murky that afternoon.
Avoid the peak monsoon months. July and August can be very rough in the Gulf. Large swells make boat travel difficult and dangerous for divers.
Comparing the two regions
The Andaman side is more intense. You will face stronger currents at Richelieu Rock. This requires a higher level of buoyancy control. Most dive shops require an Advanced Open Water certification for these trips.
The Gulf side is easier. The sites are generally shallower and calmer. This makes it better for recreational divers or those doing PADI courses. You can find many budget options here.
A trip to the Similans costs more. Expect to pay $1200 USD for a week on a boat. Koh Tao trips are much cheaper. You can find daily boat trips for 45 USD.
Choose based on your skill level. If you are a beginner, stay in the Gulf. If you want big animals, head to the Andaman.
Ethical diving practices
Rules are strict for a reason. You must never touch the shark. This behavior damages their protective mucus layer. Most dive operators will refuse to dive if they see guests touching animals.
Keep your distance. Stay at least 3 m away from the animal at all times. If the shark changes its swimming direction, you are too close. This is a rule enforced by most professional agencies like SSI or PADI.
Do not use flash photography. The sudden light can startle the animal. This might cause it to swim into a reef or a boat propeller.
Watch your buoyancy carefully. Do not kick up sand near the shark. Silt clouds make it harder for the shark to sense its surroundings.
What to pack for sightings
Bring a good underwater camera. A GoPro with a red filter works well for these deep shots. You need to compensate for the loss of red light at 15 m.
Use a dive computer. You need to track your time closely during long encounters. If a shark stays for 10 minutes, you might reach your limit quickly.
Pack plenty of sunblock. The sun is very strong on the boat decks. Choose reef-safe brands to protect the local ecosystem.
Check your fins. You need powerful fins for the Andaman currents. I prefer long fins for traveling between sites on a liveaboard.
Planning your budget
Costs vary by location. In Koh Tao, a 10-dive package is roughly 350 USD. This includes gear rental and boat fees.
Liveaboards are a larger investment. A 5-day trip in the Similans usually costs $1400 USD. This price often includes all meals and accommodation.
Do not forget travel insurance. Make sure your policy covers scuba diving up to 30 m. Check with DAN to ensure you have proper coverage for Southeast Asia.
Budget for extra dives. If you see a shark, you will want more time in the water. Having an extra $200 USD set aside is a smart move.
Final considerations for divers
Read recent dive logs. Check forums or local Facebook groups for recent sightings. This data can help you pick the right week.
Be patient with the ocean. You might see nothing but small fish. However, the chance of a sighting is worth the effort.
Respect the local guides. They know the water better than anyone else. If they say the current is too strong, listen to them.
If you have never dived in heavy currents, practice at Crystal Bay before trying Richelieu Rock.
Frequently asked questions
What are my chances of seeing a whale shark?
During peak seasons, your probability is roughly 1 in 8 to 12 dives. It depends on luck and specific site conditions.
When is the best time for the Andaman side?
The peak window is February to April 2025, when currents bring nutrient-rich water to sites like Richelieu Rock.
Is it okay to use a flash for photos?
No. You should never use flash photography because the light can stress these large filter feeders during their feeding cycles.