Andaman sea or gulf of Thailand: how to choose the coast by travel month

Choosing between the Andaman Sea and the Gulf of Thailand is not a matter of taste, it is a matter of which month you travel. In November and December the west coast delivers steady weather, while from May onward the southwest monsoon sets in there. We compared both coasts by season, ferries, prices, and travel style so you do not have to rework your itinerary on the ground.

If you are flying to Thailand for the first time, the question is simpler: Krabi and Phuket or Koh Samui and Koh Tao. Two factors decide everything here. First: when your vacation falls. Second: what kind of trip you are looking for.

In short: from November to April, choose the Andaman Sea; from June to August, choose the southern gulf. In December and January the weather on Koh Samui can be changeable, so in those months the island is not an equal substitute for the west coast.

As of seasons, ferries, and marine park closures: 09/2026, verified on the official Tourism Authority of Thailand website.

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Which coast to choose: a breakdown by priorities

💡 In short:

• First trip from November to March: Andaman Sea, with Krabi or Phuket as your base.
• Vacation in June, July, or August: southern gulf, meaning Koh Samui, Koh Phangan, and Koh Tao.
• Eastern gulf with Koh Chang, Koh Mak, and Koh Kood: plan for November to March.
• First diving course: Koh Tao.
• Rainy season and marine park closures: 09/2026, verified on the official TAT website.

Our take: with no additional constraints, we recommend the Andaman Sea from November to March and the southern gulf from June to August. For Koh Chang, Koh Mak, and Koh Kood, the best months are also November, December, and March, and more on that below.

Andaman Sea and Gulf of Thailand: comparison by criteria

The months in the table are a guideline, not a guarantee. Even in the dry season rain is possible, and in the rainy season there can be several clear days in a row. The southwest monsoon reaches both the west coast and the eastern gulf, which is why the rainy season there falls in the same months. Koh Samui runs on a different schedule, and that is the main reason the gulf as a whole cannot be treated as one climate zone.

Where the three resort regions are located

The Andaman Sea washes Thailand's west coast. This includes Phuket, Krabi, Koh Phi Phi, Koh Lanta, the islands near Trang, and Koh Lipe, and the route between them is easy to build around ferries.

In the Gulf of Thailand, keep two separate island groups in mind:

• The southern gulf is home to Koh Samui, Koh Phangan, and Koh Tao.

• The eastern gulf, near the border with Cambodia, is home to Koh Chang, Koh Mak, and Koh Kood.

Koh Samui and Koh Chang are technically in the same gulf, but their climates differ. What exactly sets the eastern group apart is covered below.

Season first, then island

If your travel month is already set, choose the coast by weather first, and the island after that. That way you will not end up at a closed beach or in a week of rain.

Best time for the Andaman Sea

From November to April the sea off the west coast is calmer and there is less rain. The Tourism Authority of Thailand gives the same period for Koh Phi Phi (as of: 09/2026, official TAT website).

From May to October the southwest monsoon arrives, bringing rain, wind, and waves. Phuket and Krabi operate year-round, but sea excursions get canceled, and on small islands some hotels close.

If you do travel in this period, choose a base with good infrastructure and do not build your plan around one specific boat trip.

Best time for Koh Samui, Koh Phangan, and Koh Tao

In the southern gulf, rain follows a different schedule. From February to September conditions are more often good, and February and March are usually the driest. June, July, and August also work well for island vacations.

From October the risk of rain rises. November on Koh Samui is one of the wettest months, and in December and January the weather can be changeable.

Best time for the eastern gulf

Koh Chang, Koh Mak, and Koh Kood are closer to the Andaman Sea in weather than to Koh Samui. The monsoon reaches both coasts in roughly the same months, and marine parks here are closed from mid-May to mid-October (as of: 09/2026, notice from the Department of National Parks).

From November to March the chances of sun and calm crossings are high. From May to October the east gets a lot of rain, the sea can be rough, and ferries between the islands become less frequent. For a summer vacation, we would not rank this group above Koh Samui, Koh Phangan, and Koh Tao.

Which coast fits your travel month

In the tropics, the forecast often shows rain even when it is just a short downpour that ends quickly. Do not look only at the rain icons. Before a boat trip, check the wind, the waves, and notices from operators on the ground.

All months in the table were checked against official sources in September 2026.

Why we choose the Andaman Sea for a first trip

© Vyacheslav Argenberg · CC BYPhoto: Vyacheslav Argenberg, CC BY (https://creativecommons.org/licenses/by/4.0), Wikimedia Commons

Around Krabi, Railay, Phang Nga Bay, and the Phi Phi Islands, limestone cliffs rise straight out of the water. For a first trip, this landscape gives you the strongest contrast with a typical beach back home, so we put the west coast first on the list.

Small bays, beaches, and islands are hidden between the cliffs. You reach them by longtail boat or ferry, and tickets are sold at piers and in hotels.

Two bases work well for a first trip: Krabi and Phuket. Both have an airport, plenty of hotels, restaurants, and excursions. For a second stop, you can add Ko Lanta, Ko Yao Noi, or Ko Lipe if you want a quiet rest after the active part.

For two weeks, plan no more than three bases. Every transfer with a ferry and minivan takes half a day, and this is the most common source of a ruined vacation.

Which Andaman Sea destinations suit you

If you want long beaches and less hustle, choose Ko Lanta rather than Ko Phi Phi. For clear water and a small island, Ko Lipe is worth the trip if you are ready to spend a whole day getting there.

What speaks for the Andaman Sea

© Nina R from Africa · CC BYPhoto: Nina R from Africa, CC BY (https://creativecommons.org/licenses/by/2.0), Wikimedia Commons

You get a very wide choice of islands, landscapes, and activities. Besides the beach, you can take a kayak, go to a climbing wall, scuba dive, or visit several bays in one day.

The region also suits different types of travel. Phuket offers infrastructure and nightlife. Ko Lanta works for long stays. Ko Yao Noi is quieter and calmer. Around Krabi, it is easy to put together a program of day trips.

What to know before deciding

From December to February, Phuket, Ko Phi Phi, and popular excursions from Krabi can be overcrowded. You should know about Maya Bay separately: it closes every year from August 1 to September 30 for nature recovery (as of 09/2026, Phuket operators' notice). Entry to the marine national park is paid, and the number of visitors on the beach is limited.

Prices also vary a lot. A quiet bay on Phuket can be expensive, while on Ko Lanta you will find accommodation in several price categories. So choose the location first, and only then the hotel.

One more point about the rainy season. From May 15 to October 15, 2026, the Similan and Surin Islands are closed to tourists by decision of the Department of National Parks (as of 09/2026, closure notice). Liveaboard dive trips do not run in these months, and the islands reopen on October 15.

Where to stay on the Andaman coast

We chose the hotels below based on location, recent guest reviews, and value for money. We do not claim to have personally verified them.

Panan Krabi Resort is in the center of Ao Nang: restaurants, the beach, and excursion meeting points are within walking distance. If you are coming for three or four days and want to visit the islands, this base saves you time on transfers, Panan Krabi Resort prices on Trip.com.

SAii Phi Phi Island Village occupies a quiet stretch of beach on Ko Phi Phi Don. People choose it when they want to see the island but not stay next to the nightlife.

On Phuket, do not decide based on the hotel alone. Kata, Karon, Patong, Kamala, and Bang Tao differ in noise, waves, and prices. Choose the area first, then the hotel.

When the Gulf of Thailand is the better choice

The Gulf of Thailand is best looked at in parts. In the southern part, a vacation works well even in the European summer. The eastern part suits the dry months and those looking for nature and less dense development.

Ko Samui, Ko Phangan, and Ko Tao

© Elmschrat · CC BY-SAPhoto: Elmschrat, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

Ko Samui has the largest hotel base and the easiest access in the southern gulf. The island has its own airport, many restaurants, and good medical care (according to the official TAT website, 09/2026). For families and for those who do not want to spend a long time planning, this is a convenient option.

The area on an island matters no less than the island itself. Chaweng, Lamai, Maenam, and the quiet southern bays differ from each other in noise, waves, and prices.

Koh Phangan is known for its parties, but it is not limited to that. The south is where the events and nightlife are concentrated. In the west and north, you will find small resorts, yoga, and calm beaches. A scooter gives you freedom, but some of the roads here are steep.

Koh Tao is worth choosing for a diving course or a few days of snorkeling. The island is compact, lively, and entirely oriented toward the water.

Koh Chang, Koh Mak, and Koh Kood

Koh Chang offers the most options among the three eastern islands. Jungle, waterfalls, beaches, and infrastructure combine here in a way that keeps the island from turning into one big resort.

© Slyronit · CC BY-SAPhoto: Slyronit, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

Koh Mak is smaller and flat. Koh Kood offers very quiet bays and good beaches, but requires more planning: you will need to arrange ferries and getting around the island in advance.

The Spa Koh Chang Resort is located in the eastern part of Koh Chang. The place is quiet, and it will suit you if nature and relaxation matter more than nightlife, prices at The Spa Koh Chang on Trip.com.

Which islands in the gulf are right for you

Where to stay in the Gulf of Thailand

We put this selection together using the same criteria: location, recent guest reviews, and value for money. We do not claim to have personally checked these hotels.

Coco Palm Beach Resort is located on the north shore of Koh Samui near Maenam Pier. The location is convenient if you plan to continue by ferry to Koh Phangan or Koh Tao.

Explorar Koh Phangan accepts guests aged 16 and over and operates on Haad Rin Nok Beach. It suits couples and solo travelers: nearby there is a pool, workspaces, and the Haad Rin area.

SALA Samui Chaweng Beach Resort opens directly onto Chaweng Beach. It is worth booking for comfort and beachfront access, not for saving money on your vacation, prices at SALA Samui Chaweng on Trip.com.

Which coast is better: beaches, diving and activities

© Wendy Harman · CC BYPhoto: Wendy Harman, CC BY (https://creativecommons.org/licenses/by/2.0), Wikimedia Commons

For landscape, we put the Andaman Sea first. Railay, Phang Nga Bay and the islands around Krabi offer limestone cliffs and small bays that you almost never see in the gulf.

Landscape and beaches

That does not mean every beach on the west coast is more beautiful. Koh Samui, Koh Phangan and Koh Kood also have light sand and clear water.

The impression usually depends on the specific bay, the season, wind and tides, not on the name of the sea. So do not choose a sea in general, choose the beach where you will spend a week.

Our picks by beach type:

• Striking landscape: Railay and the islands around Krabi.

• Long, calm beaches: Koh Lanta.

• Clear water and short transfers: Koh Lipe.

• A wide choice of beaches with infrastructure: Phuket and Koh Samui.

• Quiet bays with little development: Koh Kood.

Snorkeling and clear water

Neither coast offers clear water all year round. Rain, wind, currents, tides and boats change visibility within a matter of days.

On the Andaman Sea, we would look at Koh Lipe, Koh Kradan and the small islands near Trang. In the gulf, there are good spots off Koh Tao and Koh Kood. After several rainy days, the water turns murky in both regions.

Island hopping

© Luxure · CC BYPhoto: Luxure, CC BY (https://creativecommons.org/licenses/by/3.0/au/deed.en), Wikimedia Commons

For visiting several different islands, we would send you to the Andaman Sea. Phuket, Koh Phi Phi, Koh Lanta, Koh Mook, Koh Kradan and Koh Lipe give you plenty of route options.

In the southern gulf, the Koh Samui, Koh Phangan and Koh Tao route is easy to put together. High-speed Lomprayah catamarans and other operators run between the islands, and you should check their seasonal schedules before buying a ticket. In the eastern gulf, Koh Chang, Koh Mak and Koh Kood are also visited one after another, but the schedule depends on the season and the weather. Excursions and tours on GetYourGuide help cover day trips where the ferry does not run every day.

Diving and marine parks

For a first diving course, we choose Koh Tao. The island has many schools, the sites are nearby, and there are courses for beginners.

© KOSIN SUKHUM · CC BY-SAPhoto: KOSIN SUKHUM, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

Experienced divers will find the west coast more interesting: the Similan and Surin Islands, Koh Lipe and Koh Phi Phi. Some marine parks close during the rainy season, so check the dates in official announcements before your trip (as of 09/2026, Nation Thailand).

Traveling with children

We put Koh Samui and Koh Lanta first for families. Koh Samui has many resorts, its own hospital and an airport. Koh Lanta is quieter, with long beaches and enough restaurants for a longer stay.

Phuket has the widest choice of activities, but the specific beach matters a lot here. If you are traveling with small children, check currents, depth, rocks and waves for the season.

Nightlife

For clubs and a wide choice of bars, we would send you to Patong on Phuket. The Chaweng area on Koh Samui also has plenty of bars and beach clubs.

Koh Phangan is known for the full moon party, but outside those dates the island has quiet areas.

Koh Lanta, Koh Yao Noi, Koh Mak and Koh Kood are better suited to quiet evenings at a restaurant or a small beach bar.

How to get there and how much it costs

© Preecha.MJ · CC BY-SAPhoto: Preecha.MJ, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

Getting to the Andaman Sea

© Roma Neus · CC BYPhoto: Roma Neus, CC BY (https://creativecommons.org/licenses/by/3.0), Wikimedia Commons

Phuket and Krabi have international airports, and many domestic flights depart from Bangkok. Buses, minivans and taxis run from both airports to the resorts.

In season, ferries and speedboats run to the islands. To reach Koh Lipe, people usually travel via Hat Yai and Pak Bara, and the journey takes almost a full day, so leave yourself a time buffer.

Getting to Koh Samui, Koh Phangan and Koh Tao

© MNXANL · CC BY-SAPhoto: MNXANL, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

The fastest way to Koh Samui is by plane, but those tickets are often more expensive than flights to Phuket, Krabi or Surat Thani.

A combined bus and ferry ticket via Surat Thani is usually cheaper. An overnight train from Bangkok with a transfer to the pier is also possible. Koh Phangan and Koh Tao can only be reached by water.

Getting to Koh Chang, Koh Mak and Koh Kood

© zhaffsky · CC BY-SAPhoto: zhaffsky, CC BY-SA (https://creativecommons.org/licenses/by-sa/2.0/), Flickr

Most people travel from Bangkok by bus or minivan to Trat, while some choose to fly. After that, you take a ferry to your island. For Koh Mak and Koh Kood, watch the last departure of the day: missing it means an overnight stay on the mainland.

On Phuket and Ko Samui, it is convenient to rent a car at the airport if you plan to drive around the island a lot, compare car rental prices.

Where vacations are cheaper

No coast is consistently cheaper. The price is determined by the island, season, beach line, and comfort level.

On Ko Samui and Phuket, there are both expensive resorts and plenty of simple accommodation with inexpensive restaurants.

On small islands, transport, groceries, and beachfront hotels cost more: there is less choice, and goods are brought in by boat. Compare prices on a specific island rather than the average cost across the sea.

Is it worth visiting both coasts

For two weeks, we recommend staying on one coast. Traveling between the west and the east usually takes a full day: a flight, a bus, waiting, and a ferry.

From three weeks onward, both coasts start to make sense. There are direct flights between Phuket and Ko Samui; in other cases, you travel via Bangkok or overland through Surat Thani. Check the current schedule before booking hotels, and you can compare domestic flights within Thailand in advance.

For two weeks, we would choose one of these routes:

Adjust the route to your arrival. Before your international flight home, leave at least one night on the mainland or near the airport.

Common mistakes when choosing a coast

• Treating the entire gulf as one climate zone. Ko Samui and Ko Chang have different rainy seasons. Check the specific island.

• Planning too many islands. Every transfer takes up most of the day.

• Booking the ferry after the hotel. First check whether you can make it to the island on your arrival day.

• Flying home right after a ferry crossing. Wind and waves delay boats. Leave yourself a time buffer.

• Choosing based on beach photos. Tides, low tide, monsoon, and boats change the color of the water.

• Booking late during holidays. At Christmas, New Year, and during European school holidays, good beachfront hotels get booked up in advance.

• Ignoring waves and tides on small islands. On Ko Lipe and Ko Kut, boats are canceled due to wind, and the island becomes less accessible exactly on the days when you planned to travel.

Our coast recommendation

For a first trip from November to March, we choose the Andaman Sea. Krabi or Phuket gives you a convenient base. Then Ko Lanta, Ko Yao Noi, or Ko Lipe can become a second, calmer stop.

In June, July, or August, we would go to the southern gulf. Ko Samui offers the most comfort, Ko Phangan the most variety, and Ko Tao the best conditions for a diving course.

If nature and a long stay on one island matter more to you, choose Ko Chang and plan your trip from November to March. Then you can add Ko Mak or Ko Kut.

One more point about dates. From mid-May to mid-October, the rainy season runs along the Andaman Sea and in the eastern gulf. The southern gulf follows a different schedule during these months. If your vacation falls in this period, choose the southern gulf and a hotel with free cancellation.

The takeaway is simple: first the month, then the type of vacation, and only then the specific island. That way you will end up not just on the right coast, but in a place that suits your trip.

⁉️🤔 Frequently asked questions

Which is more scenic: the Andaman Sea or the Gulf of Thailand?

If landscape matters to you, the Andaman Sea wins. Limestone cliffs, bays, and small islands around Krabi and Phang Nga give you views that are rare in the gulf. For quiet sandy beaches, Koh Samui, Koh Phangan, and Koh Kood look just as good. Don't rely on photos alone: also check the month you're traveling, because in the rain any bay loses its water color.

Which coast is better in July and August?

In July and August, go with Koh Samui, Koh Phangan, or Koh Tao. The west coast and the area around Koh Chang get more rain during these months, and the sea is often rough. The southern gulf usually has milder weather, though short downpours happen there too. If your vacation falls in these months, pick an island with well-developed infrastructure.

Which coast is better in November?

In November, we recommend the Andaman Sea or the eastern gulf with Koh Chang, Koh Mak, and Koh Kood. Around Koh Samui, November is one of the rainiest months, so a beach vacation there may not work out. On the west coast, the weather is already improving, but the first weeks of the month are still changeable. Book a hotel with free cancellation.

Which coast is better in December?

In December, the west coast and the eastern gulf are the most reliable: Koh Chang, Koh Mak, and Koh Kood. On Koh Samui, the weather at the start of the month can still be changeable, but by late December it usually settles down. Book holiday dates in advance: good beachfront hotels get snapped up by fall. Keep in mind that from December to February, Phuket and Phi Phi are crowded with tourists.

Where is the best snorkeling?

Both regions have good spots: Koh Lipe, Koh Kradan, Koh Tao, and Koh Kood. Visibility depends on the season, wind, rain, and currents, so neither side wins year-round. After several rainy days, the water gets murky everywhere. If snorkeling is your priority, choose the island rather than the sea, and go early in the morning while there are still few boats around.

Where is the best place to learn diving?

For a first course, we choose Koh Tao. The island has many schools, dive sites are close by, and beginner courses run year-round. Training usually takes three or four days and includes guided dives with an instructor. The west coast is better suited to experienced divers: the Similan and Surin Islands are open from mid-October to mid-May.

How many nights should you plan for one island?

On Koh Samui, Koh Chang, or Phuket, it makes sense to allow four to seven nights. Much depends on whether the island is part of a route or the main goal of the trip. On small islands, three to five nights is enough. For two weeks, we suggest no more than three islands, otherwise you'll be counting travel days instead of beach days.

Can you see both coasts in two weeks?

Technically you can, but we wouldn't plan it that way. Between the west and the east, you lose almost a full day in transit: a flight, a bus, waiting, and a ferry. With two weeks, one side gives you more time for beaches, excursions, and relaxed days. If you have three weeks or more, both coasts fit into a single itinerary.

In short: what to book

If your vacation is from November to March and it's your first trip to Thailand, go with Krabi or Phuket, then add Koh Lanta.

If you're traveling in June, July, or August, go with Koh Samui and add Koh Phangan.

If you want quiet and nature, go with Koh Chang from November to March, then Koh Mak or Koh Kood.

To get started, two bookings are enough: accommodation and excursions. See Thailand hotels on Trip.com and check tours on GetYourGuide. You can arrange the rest on the spot.