Island guides
Thailand islands
Thailand has two distinct island coasts with different characters, seasons, and practical logistics. Choosing the right coast comes before choosing the right island.
Andaman Sea vs Gulf of Thailand
How the two coasts differ
Andaman Sea — west coast
Phuket, Krabi, Koh Phi Phi, Koh Lanta, and the Similan Islands sit on the Andaman side. This coast is known for dramatic limestone karst scenery, clear water from November to April, and strong diving from Khao Lak to the outer islands.
The southwest monsoon closes large parts of the Andaman coast from May to October. High season is December to March. If scenery and diving are the priority, this is the stronger coast.
Gulf of Thailand — east coast
Koh Samui, Koh Phangan, Koh Tao, and Koh Chang sit in the Gulf. The seasons here are offset from the Andaman — the Gulf is often workable when the west coast is closed, though Samui has its own rainy window in November.
The Samui–Phangan–Tao chain is the most coherent Gulf itinerary: three islands with distinct personalities within easy ferry distance of each other. Koh Tao in particular is one of the world's most accessible dive training destinations.
Practical note: Most visitors only visit one coast per trip — the logistics of crossing from Andaman to Gulf add a full travel day. Decide which coast suits your travel window first, then narrow to specific islands.
Quick reference
Island comparison at a glance
A starting point only — use the individual island guides for anything you might actually act on.
| Island | Coast | Known for | Guide |
|---|---|---|---|
| Koh Samui | Gulf of Thailand | Chaweng Beach, Big Buddha | Read guide |
| Koh Phangan | Gulf of Thailand | Full Moon Party, Haad Rin Beach | Read guide |
| Koh Tao | Gulf of Thailand | Diving & Snorkeling, Sairee Beach | Read guide |
| Koh Phi Phi | Andaman Sea | Maya Bay, Viewpoint Hike | Read guide |
| Koh Lanta | Andaman Sea | Long Beach, Mu Ko Lanta National Park | Read guide |
| Koh Chang | Gulf of Thailand | White Sand Beach, Klong Plu Waterfall | Read guide |
| Koh Lipe | Andaman Sea | Pattaya Beach, Walking Street | Read guide |
| Koh Yao Noi | Andaman Sea | Phang Nga Bay Views, Rice Paddies | Read guide |
| Koh Mak | Gulf of Thailand | Ao Kao Beach, Cycling | Read guide |
| Koh Samet | Gulf of Thailand | Sai Kaew Beach, Fire Shows | Read guide |
| Phuket | Andaman Sea | Patong Beach, Big Buddha | Read guide |
Continue planning
Related guides
Thailand islands — planning guide
Covers how to choose between coasts, how many islands to include in a trip, and which combinations work logistically.
Best beaches in Thailand
Organised by beach character rather than island name — useful when you know the kind of shore you want but not which island to anchor on.
Island vs island comparisons
Side-by-side breakdowns of specific island pairs. Most useful once you have a shortlist of two realistic candidates.
Sources
Editorial notes and sources
Island data was reviewed against official Tourism Authority of Thailand destination pages in March 2026. Season windows and transport information are intentionally broad — exact ferry schedules and park opening dates change seasonally and should be confirmed closer to travel.