Quick Answer
Best Islands in Thailand
Thailand's islands split between the Gulf of Thailand (east coast: Koh Samui, Koh Phangan, Koh Tao) and the Andaman Sea (west coast: Phuket, Phi Phi, Koh Lanta, Koh Kradan). The Andaman islands are more dramatically beautiful with limestone cliffs and clear turquoise water; the Gulf islands are more accessible from Bangkok and have their own charm. Koh Tao is unrivalled for learning to dive. Phi Phi is the most iconic scenery. Koh Lipe is Thailand's most remote paradise beach. Koh Samui is the best-developed large island on the Gulf side.
Category Scores
Phuket
Best for: maximum variety, island hopping, nightlife, international access.
Koh Phi Phi
Best for: iconic scenery, snorkelling, Instagram-worthy bays, backpackers.
Koh Tao
Best for: diving courses (cheapest PADI certification in the world), snorkelling.
Koh Samui
Best for: large island infrastructure, families, easy Gulf access.
Koh Lipe
Best for: remote paradise beaches, snorkelling, minimal development.
Koh Lanta
Best for: long-stay digital nomads, quiet beaches, Andaman sunsets.
Detailed Comparison
Andaman Islands — Phuket, Phi Phi, Lanta, Lipe
Phuket winsPhuket
The Andaman Sea's islands are widely considered Thailand's most beautiful. Phuket is the hub with its own international airport. From Phuket you can day-trip to Koh Phi Phi (2 hours by speedboat — the setting for The Beach), explore Phang Nga Bay's limestone karsts (James Bond Island), and reach the Similan Islands (some of the world's best diving). Koh Lanta sits 2 hours from Krabi with a 27km stretch of beaches on the west coast. Koh Lipe, near the Malaysian border, requires a speedboat from Pakbara or a ferry from Langkawi — the remoteness keeps it beautiful.
Koh Tao
Koh Phi Phi Don is the inhabited island in the Phi Phi group. Tonsai village concentrates all accommodation and restaurants; quieter bays like Lo Bakao and Laem Tong at the north end offer resort seclusion. The famous Maya Bay (where The Beach was filmed) was closed for rehabilitation 2018–2022 and now has timed-entry snorkelling. Diving around Phi Phi is excellent — shark Point and Anemone Reef are outstanding sites accessible as day trips.
Gulf Islands — Samui, Phangan, Tao
TiePhuket
Koh Samui is the Gulf's largest developed island with the infrastructure to match: Bangkok Hospital, international schools, and direct flights. Koh Phangan, 30 minutes by ferry from Samui, is famous worldwide for its Full Moon Party on Haad Rin beach (monthly, draws 10,000+ people) but is quieter and beautiful away from the party scene. Srithanu village on the west coast has a yoga/wellness community.
Koh Tao
Koh Tao is a 45-minute speedboat from Koh Phangan or 2 hours by ferry. Despite being only 21 km², it has more dive schools per capita than almost anywhere on earth. A PADI Open Water certification costs ฿9,000–11,000 here vs ฿18,000+ in most other countries. Snorkelling directly from beaches at Japanese Garden and Shark Bay is excellent without any boat.
Remote & Off-the-Beaten-Path Islands
TiePhuket
Koh Kradan in Trang province has pristine beaches and a coral reef you can snorkel directly from the shore. Koh Muk features the Emerald Cave (Tham Morakot) — accessible only by swimming through a dark sea cave to emerge in a hidden lagoon. Koh Libong is a dugong conservation zone. These islands are best reached March–May before monsoon.
Koh Tao
Koh Chang (Trat province, Gulf coast) is the second largest island after Phuket and remains under-developed relative to its size. Excellent diving in the Koh Chang Marine National Park. White Sand Beach and Klong Prao Beach are attractive. Proximity to Cambodia makes it a popular stop on Bangkok–Siem Reap routes. Slower tourism development means better prices and less crowds.
Our Verdict
Thailand has over 1,400 islands. The best choice depends entirely on whether you want diving, parties, beaches, or seclusion.
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