🔄 Updated 26 Jun 2026
What makes Thailand such a great diving destination is warm water year-round, lower course costs compared with most countries, and a huge variety of sites — from shallow beginner bays all the way to deep rock pinnacles where whale sharks and manta rays pass through in season. The only planning decision is choosing the right coast for the month you're visiting.
Where to Dive
| Destination | Sea | Best Season | Known For |
|---|---|---|---|
| Koh Tao | Gulf of Thailand | Almost year-round (avoid Oct–Dec) | Best-value Open Water certification, many dive schools |
| Similan Islands | Andaman | 15 Nov–Apr (closed during monsoon) | Crystal-clear water, stunning rock formations, liveaboards |
| Koh Phi Phi / Hin Daeng–Hin Muang | Andaman | Nov–Apr | Coral walls, sharks, deep-water sites |
| Koh Lipe | Andaman | Nov–Apr | Clear water, shallow reefs, good for beginners |
| Samui / Phangan / Hin Bai | Gulf of Thailand | Almost year-round | Casual diving near the islands, whale sharks in season |
Learn to Dive on Koh Tao (Book on Klook)
Koh Tao Dive Courses with the Most Bookings
Koh Tao is one of the most affordable places in the world to earn a dive certification. These courses are from PADI 5-Star centers — click through for live availability, current prices, and real reviews.
PADI Open Water Diver (3-day)Your first certification — dives to 18 m, lifetime card valid worldwide. The course to take if you're serious about diving. Klook 
Discover Scuba Diving (intro dive)No certification required — pool briefing then 2 real dives with an instructor right beside you. Perfect for trying before committing. Klook 
PADI Advanced Open WaterThe next step after Open Water — dives to 30 m, adds navigation and deep-dive specialty skills. Klook Dive Trips & Snorkeling on the Andaman Coast (Book on Klook)
Similan & Andaman Trips with the Most Bookings
The Andaman coast is celebrated for its crystal-clear water and Thailand's top dive sites. The Similan Islands are open only around 15 Oct–15 May — day trips include van + boat transfers and suit both snorkelers and certified divers.
Similan Islands Day Trip (Phuket/Khao Lak)Full day, back same evening — includes hotel pickup. Multiple snorkel stops at some of Thailand's clearest water. Klook Similan Islands Snorkeling Speedboat (Seastar)Speedboat from Phuket, stops at the most popular snorkel spots. Great for families and first-timers. Klook Seasons: Gulf of Thailand vs Andaman
The core planning decision is which coast you're on. The Andaman coast (Phuket, Phi Phi, Similan, Koh Lipe) has clear water and calm conditions Nov–Apr. The Similan Islands, a national park, are open only around 15 Oct–15 May and then close for the monsoon to allow natural recovery. The Gulf coast (Koh Tao, Samui, Phangan) is diveable almost year-round; the period to avoid is heavy rainfall Oct–Dec. So if you arrive on the Andaman coast during monsoon season, you can simply switch to the Gulf side instead.
💡 Dive Safely and Get the Most Value
Arriving on the Andaman coast during monsoon (May–Oct)? Switch to the Gulf side instead. For Similan, you must come during the open period: 15 Oct–15 May.
After deep dives, wait at least 18–24 hours before boarding a flight. Schedule your dive days so they don't clash with your departure day.
Check whether the school is a PADI or SSI center, read reviews, and ask about the instructor-to-student ratio before booking.
Don't touch or stand on coral, don't feed fish, and use reef-safe sunscreen.
Plan your dive trip — pick the right island and the right time, then map it into a day-by-day itinerary.
Start Planning Your Trip →