Last Updated on December 3, 2021

Did you know that Thailand has over 340 named dive sites spanning from the southern tip of the Andaman Sea to the northern end of the Gulf of Thailand? It is just one of many reasons that scuba diving in Thailand, the Land of Smiles, should be high on your list.

Thailand features some incredible marine life, vibrant reefs full of color, not to mention beautiful warm water at any time of year.

With so many great islands at which to base yourself, complete with delicious, cheap cuisine, it can be a difficult challenge deciding where to go.

So, let’s take a look at all you need to know about the where, when, and how!

1. The Andaman Sea or the Gulf of Thailand?

Diving in Thailand is generally broken up into two sections, the Andaman Sea on Thailand’s west coast and the Gulf of Thailand on the other side.

There are many similarities between the two diving regions, both come with stunning underwater worlds, and both are fit for beginners through to experts, without costing an exorbitant amount.

That’s right, wherever you go, Thailand is one of the cheapest countries in the world for scuba diving, whether you’re learning or a seasoned expert.

Thailand’s two major diving locations though operate on different schedules so let me explain the time scales below for each.

2. Best Time for Scuba Diving in Thailand

The best time to make your way to the Andaman Sea is between November and April.

Keep in mind peak season coincides with the height of tourist season in December and January.

Crowds can be high but diving in the outside of those two months will give you greater space.

The best time to dive in the Gulf of Thailand is May to October, which means you can switch between the two all year round and not miss a beat.

Off-season diving is always an option in Thailand if you want to get away from the crowds. Krabi, Koh Phi Phi, and Phuket in the Andaman Sea can be dived at any time of the year.

The best time to witness whale sharks and manta rays in the Gulf is to go diving between February and May.

3. Dive Centre or Liveaboard

For newbies to the diving scene, it is important to know the difference between these two options and how they can impact your trip.

A liveaboard is a boat specifically designed to lead scuba diving trips away from land.

This is the perfect choice to experience dive sites that are harder to access and you won’t have to return to your resort every night.

For those that want to eat, sleep, dive repeat, a liveaboard will be right up your alley.

However, for overnight liveaboards, there’s a good chance you won’t know your roomies.

You will also be on the move when you aren’t diving, so if you battle seasickness, ask yourself if this is the right option for you. If so, load up on some seasick tablets just in case.

While there are plenty of liveaboards in Thailand, dive centers remain more common and will be in all locations.

If you just want to do a single dive and enjoy some time on land afterward, then this is a more laidback option.

In this case, a dive center is also the perfect spot to begin your scuba diving life.

4. Similan Islands – For a Whale Shark and Manta Ray Adventure

The Similan Islands are a famous scuba diving destination in Thailand and are often rated as one of the best places in the world to dive.

A total of nine islands combine into the otherworldly, Mu Ko Similan National Park.

The marine life here is extensive to say the least, with impressive corals and an array of sea life with the highlight being the manta rays that flock to this region between December and April.

The visibility here is off the charts, and there are a number of specific sites that will put a huge smile on your face.

Make sure your liveaboard outfit includes Christmas Point, Ko Bon West, and Koh Tachai on their itinerary.

In order to limit visitors, the only way to dive in the Similan Islands is to join a liveaboard which will cost around 120USD per day, inclusive of board, gear, and food.

Info & How to Get to the Similan Islands

  • Season: October to May
  • Water Temp: 28-30C (83-87F)
  • Difficulty: Beginner to Advanced
  • How to Get There: Fly into Phuket Airport
  • Where to Stay: On Liveaboard

5. Koh Tao – Learn to Dive

Located in the Gulf of Thailand, Koh Tao isn’t just known for excellent diving, it is also one of the cheapest places to be certified in Open Water Diving.

Koh Tao also has a vibrant nightlife and stunning dive sites providing prospective divers with great dive/life balance.

Highlights of diving in Koh Tao include mesmerizing rock formations, swim-throughs, and tunnels with the giant granite protrusions being the most popular sites.

Aside from deep walls, you can swim with whale sharks off the southwest coast for a more adrenalin-pumping experience.

Due to cost and ease of access, Koh Tao is a particularly great spot for beginner divers.

Liveaboards aren’t found here, so linking up with a dive center is the way to go

Info & How to Get to Koh Tao

  • Season: March to October
  • Water Temp: 26-30C (78-87F)
  • Difficulty: Beginner to Advanced
  • How to Get There: Fly or Ferry direct to Koh Tao

6. Koh Chang – Resting Place of HTMS Chang

Koh Chang is Thailand’s second-biggest island and comes packed with amazing dive sites, along with easy access to Koh Rang National Marine Park.

Koh Chang sees fewer divers, so there is a chance to break the mold and see Thailand from a different angle.

Dive sites here come teeming with rays, turtles, corals, canyons, and pinnacles.

A visit to Koh Rang will give you the opportunity to dive next to massive rock walls, covered in beautiful coral. Alongside you will be numerous great barracudas, cobias, and tunas.

The real highlight however is Thailand’s biggest wreck, the 117m (380ft) HTMS Chang. Explore cabins, holding areas, and briefing rooms now home to diverse sea life.

Info & How to Get to Koh Chang

  • Season: November to April
  • Water Temp: 27-31C (80-88F)
  • Difficulty: Beginner to Advanced
  • How to Get There: Fly from Bangkok to Trat, then ferry to Koh Chang

7. Surin Islands – Unique Sealife

The Surin Islands are protected under the UNESCO environmental program, leaving a spectacular, untouched natural world waiting for you.

The numerous dive sites here come with unique species of fish not found anywhere else in Thailand, due to the low level of tourism.

Soft and hard coral is found in abundance, creating a diverse world for you to explore, one that changes around every corner.

With its location within the Mu Ko Surin Marine National Park, the area is closed to divers for much of the year.

But during dive season, you will be able to explore this incredible place on a liveaboard. Keep an eye out for the trip to Richelieu Rock, arguably the best individual site in Thailand.

Info & How to Get to the Surin Islands

  • Season: October to Early May
  • Water Temp: 28-30C (83-87F)
  • Difficulty: Intermediate to Advanced
  • How to Get There: Fly/Bus to Phuket then on to Khao Lak

8. Koh Phi Phi – Diving and Nightlife

Koh Phi Phi remains a popular dive destination owing to its accessible location, colorful nature, and beginner dive sites.

A total of 6 islands make up the Koh Phi Phi archipelago, made famous by the movie ‘The Beach’, and its striking scenery continues to bring back divers and travelers alike.

There are a number of impressive dive sites to be found here, with manta rays and whale sharks known to be found here, while it remains one of the best places to stumble upon leopard sharks.

Dive centers and liveaboards both operate on Koh Phi Phi giving you a variety of options to choose from.

Liveaboards offer great bang for your buck, but Koh Phi Phi Don’s famed nightlife will have you tempted to return to dry land every night.

Info & How to Get to Koh Phi Phi

9. Koh Samui – Great Visibility

Koh Samui is an excellent option for year-round scuba diving.

Although being a busy tourist destination puts off potential divers, it is still one of the best places to dive in Thailand, and the phenomenal Sail Rock site is close by.

Koh Samui sees a range of diverse sea life, macro lovers will witness shrimp and nudibranch. Turtles, barracudas, and whale sharks also make themselves at home here and deep dives will lead you to stingrays.

Another popular site is the Southwest Pinnacles, featuring broken granite walls of hard and soft corals. Here you’ll find leopard sharks, jacks, and barracudas.

Info & How to Get to Koh Samui

  • Season: Year-round (main season: Jan-Aug)
  • Water Temp: 28-30C (83-87F)
  • Difficulty: Beginner to Advanced
  • How to Get There: Fly direct or ferry from Surat Thani When it comes to choosing the best place to dive in Thailand, it helps to narrow down your goals.

Do you wish to do nothing but dive for a week?

A liveaboard and a trip to the remote Surin or Similan Islands may be the way to go.

If you want to enjoy Thailand below and above the water, popular spots like Koh Phi Phi and Koh Tao will have you living the best of both worlds.

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