Diving Thailand in April: Where to Dive, Conditions and Trip Planning

Featured image: WordRidden, CC BY 2.0, via Flickr.

Diving Thailand in April: Is It a Good Month?

Yes, with caveats. Published dive guidance puts the best Thai diving window at November through April, so April is the last month of it. The Andaman side has calmer water during the northeast monsoon, which runs December through April.

The Gulf of Thailand has its own best season, May through November. April falls outside it. Our pick for most April trips is therefore Phuket, Khao Lak or Koh Lanta, not Koh Tao. We'd keep the Gulf for short trips or courses where flight convenience matters more than site quality.

April Dive Conditions: What to Expect

April closes the dry window. We can't promise April visibility or sea-state numbers, and we won't invent them. Tides and currents change the picture from day to day. A dive guidebook puts Shark Point visibility anywhere from 4 m to over 25 m.

Use Thailand's monthly water temperatures to plan your exposure suit. For the month before, read diving Thailand in March. For the shoulder period that follows, see diving Thailand in May.

The practical effect of the season ending is site access. Some sites close during monsoon season, so April is the month to book early and stay flexible on dates.

Andaman Sea vs Gulf of Thailand in April

Here is how the two coasts compare for an April trip. Old forum debates about Koh Tao split sharply. Some divers praised Sail Rock and Chumphon Pinnacle. Others called most other sites crowded and worn. Treat those posts as dated opinion, not current fact.

Phuket and Koh Phi Phi

Phuket is the easiest day-trip base. Phi Phi suits divers who want island life, and its local sites are at most about 30 minutes away by fast boat.

We'd put these sites on a first list:

Shark Point and Anemone Reef sit about 16 nautical miles from Phuket. The King Cruiser car ferry sank on Anemone Reef in 1997. Its stern lies at 34 m and its bow at 14 m, so the deep end needs the right certification. Racha Yai is about 2 hours by dive boat. It suits training dives more than showpiece diving.

One reviewer of a Phuket operator advised skipping Racha Noi, saying there is not much to see. That is a single opinion. The long days are the real trade-off, since some multi-dive trips leave around 7:30 and return late evening. Kata Beach has shore and night diving. Check current access before you plan around it.

• Shark Point and Anemone Reef: coral bommies, strong current possible
• King Cruiser wreck: stern 34 m, bow 14 m, deep-dive certification needed
• Racha Yai: about 2 hours by dive boat, best for courses
• Phi Phi local sites: at most about 30 minutes by fast boat

Khao Lak and the Similan Islands

Khao Lak is the main liveaboard departure point on this coast. Single-day and overnight cruises exist. We'd still choose a multi-day liveaboard if you have the time, because the best sites are far out. The Similans lie roughly 60 nautical miles northwest of Phuket, and the islands have no accommodation.

Liveaboards from here typically visit Similan sites such as Elephant Head Rock, East of Eden and Beacon Point. They also reach Koh Bon, known for manta sightings, and Richelieu Rock, known for whale sharks. Treat any April sighting as a possibility, not a promise.

Park season is the key check. Some operators say Khao Lak diving runs only November to April. Read the national parks department's season notices for current Similan and Surin opening dates. We won't quote a closing date from memory, and April may sit right at the edge.

Koh Lanta, Hin Daeng, Hin Muang and Koh Haa

Koh Lanta is road-accessible and quieter. From here you can reach two remote sites. Hin Daeng and Hin Muang are sister rock formations with drop-offs and coral gardens. Koh Haa is made up of six uninhabited limestone islands, where hawksbill turtles and ghost pipefish turn up.

The extra transfer is the cost. Expect a long boat day from Lanta, or a liveaboard stop. We'd pick this base if crowds bother you more than travel time does.

Koh Lipe and the South

Koh Lipe is car-free and sits inside Tarutao National Marine Park, just north of the Thai-Malaysian border. Its underwater rock formations and leafy coral gardens are the draw.

The nearest airport is Langkawi in Malaysia, so you cross a border by boat. Check current ferry routes before you commit. We'd only add Lipe to April trips of a week or more.

Day Trip, Liveaboard or Base Island

Each format suits a different traveler. This table sets out the trade-offs, followed by the mistakes we'd steer you away from.

• Booking a Similan trip without checking park season dates
• Choosing the King Cruiser's deep end without the right certification
• Packing too many dives into one long day trip
• Assuming a Gulf course will match Andaman site quality

Sample April Itineraries

We treat these as route and time trade-offs, not fixed plans.

• 3 days, Phuket base: day trips to Shark Point, Anemone Reef and the King Cruiser, then Racha Yai.
• 5–7 days: Phuket day trips, then transfer to Khao Lak for a liveaboard to the Similans.
• Short trip: stay on Phi Phi for two or three nights and dive the local sites by fast boat.
• Two weeks: Koh Lipe, Koh Lanta, Phuket and Khao Lak, ending on a liveaboard. This south-to-north route can be reversed.

Costs and Booking Trade-Offs

We have no current rate we trust, so ask operators for dated quotes. What drives cost is clearer. Liveaboards cost more than day trips. Packages usually let you book first and pick dive days on arrival. Courses cost differently from fun dives. A Phi Phi base saves boat time but costs more in accommodation. Prices and hours checked November 2026.

Safety, Medical and Gear Notes

Phuket has hyperbaric services, including one in Patong, plus Vachira Phuket Hospital and Bangkok Phuket Hospital. Confirm current facilities before travel. Carry dive insurance. Consider nitrox or deep courses for wrecks. Bring seasickness tablets if you are new to liveaboards.

Other Months in the Thailand Dive Series

Compare nearby seasons before you lock dates. January and February fall earlier in the dry window. After May come June, July and August. Later months include September, October, November and December.