Thailand’s Andaman coast is the west-facing Indian Ocean shore: about 740 km from Ranong at Myanmar down to Satun near Malaysia. Karst towers, green water, mangrove, and some of the richer reefs in the east Indian Ocean. Exposure means currents, depth, and a southwest monsoon (May–October) that closes islands. November–April is the season the photographs were taken in.
The other sea is the Gulf, and it is often good when this one is not. Which coast. Mu Ko Similan closed about 16 May–14 October 2026. Park fee commonly ~500 THB foreign adult; daily cap cited 3,850. Park permits.
Phang Nga — karst as a kingdom
Phang Nga Bay: shallow water, hundreds of limestone islands, vertical walls in vegetation. Hongs are collapsed caves you kayak into through a dark slot and out into a hidden lagoon. That sentence is why people book Krabi.
- James Bond Island (Ko Khao Phing Kan) — The Man with the Golden Gun (1974). Touristy. Still geology.
- Hong Islands — paddle the dark, come out in a green room.
- Ko Panyi — Muslim fishing village on stilts, ~2,000 people, floating football pitch that became a commercial.
Khao Lak
North of Phuket. Wider beaches, hills, families, the mainland door to the Similans (~80 km offshore). 2004 tsunami memorials include a police boat carried 2 km inland. That is not a metaphor. Phuket.
Krabi — limestone you have to boat to
- Railay — no road; longtail only. White crescent, 700+ sport-climbing routes on the karst. East = landing; West = swim; Phra Nang = cave shrine.
- Ao Nang — the town, the restaurants, the boats.
- Tiger Cave Temple (Wat Tham Suea) — 1,237 steps. Modest dress. Temple etiquette.
- Emerald Pool and hot springs — forest, thermal stream, green water.
Four Islands day: Ko Poda, Ko Gai (Chicken Island), Tup (sandbar at low tide), Phra Nang Cave Beach. Last boats are real. Krabi, Best beaches.
Trang and Satun — quieter on purpose
Trang:
- Ko Muk — Emerald Cave (Tham Morakot): swim 80 m of dark passage to a beach inside a chimney of cliff. Extraordinary. Not a stunt if you cannot swim.
- Ko Kradan — the “most beautiful beach” list regular; often empty.
- Ko Libong — best wild dugong odds in Thailand.
Satun:
- Ko Lipe — southernmost resort island, Walking Street snorkel trail, Chao Ley community.
- Ko Tarutao — WWII-era political prison, now park. Monitors, langurs, hornbills, empty sand, almost no nightlife.
- Ko Adang and Ko Rawi — jungle walks, viewpoints, Tarutao archipelago.
Coastline and islands, National parks overview.
Marine life
Deeper, richer water than the Gulf:
- Whale sharks — Similan/Surin, especially February–April, 12 m+
- Mantas — cleaning stations, Koh Bon among them
- Leopard sharks — bottom, many sites
- Reef fish: clownfish, lionfish, parrotfish, morays, Napoleon wrasse, barracuda, trevally
- Hawksbill and green turtles — Similan nesting often November–February
Coral reefs, Dive sites, Snorkel or dive. Bleaching years 2010, 2016, 2024. Maya Bay’s cap exists because the uncapped version failed.
| Pin (2026) | Figure |
|---|---|
| Andaman coast length | ~740 km |
| Similan close | ~16 May–14 Oct 2026 |
| Similan foreign adult | ~500 THB |
| Similan daily cap (cited) | 3,850 |
| Railay access | Longtail only |
| Wat Tham Suea | 1,237 steps |
| Emerald Cave swim | ~80 m dark |
| Maya Bay close (recovery) | 2018–2021; timed caps since reopening |
| 2004 tsunami (TH deaths) | ~5,395, worst at Khao Lak and Phi Phi |
Moken
The Moken (Chao Ley) are Austronesian sea people, historically boat-nomads. Communities remain on Surin and some coasts. Extraordinary free-divers. Many survived 2004 by reading the sea and going high. Modern borders, park zones, and tourism squeeze the life that knew the warning. Visit as guests, not as a photo set.
Four hubs, not one beach
Phuket is the international door (bridged at Sarasin, airport). Khao Lak is the Similan mainland — the ~80 km run to the nine islands. Krabi / Ao Nang is the karst and the Railay longtail pool (Ao Nang or Ao Nam Mao). Trang and Satun are slower on purpose: dugong at Libong, the 80 m dark of Tham Morakot, Tarutao as a park overnight.
| Site | Access pin (2026) |
|---|---|
| Mu Ko Similan | Closed ~16 May–14 Oct; foreign adult ~500 THB; daily cap cited 3,850 |
| Mu Ko Surin | Same monsoon close; Moken villages; snorkel flats more than walls |
| Maya Bay (Phi Phi Leh) | Timed landings after the 2018–2021 close; no freelance longtail onto the sand |
| Railay | Longtail only; last boats are a curfew, not a vibe |
| Ko Lipe | Speedboat from Pak Bara (Satun); Walking Street reef is the snorkel |
| Ko Tarutao | Park overnight; monitors and empty sand, not nightlife |
Tsunami memorials at Khao Lak include a police boat carried 2 km inland on 26 December 2004. Early-warning towers exist now. They do not make a red-flag swell safe. Park permits, Dive sites.
When to come
- November–April — dry, calm, visibility. December–January is peak price and peak crowd.
- May–October — rain, swell, closed Similans/Surins, some Phi Phi services off. Hotels cheaper. Mainland Krabi and Khao Lak still exist; your daily snorkel does not.
Gulf alternative in the wet: Samui/Tao/Phangan, or Trat. Monsoon seasons, Gulf coast.
A dry bag 10 litre, snorkel mask, rash vest. Cash at park piers. Last return on the ticket.
Gateway logistics: Getting there, When to visit. Inland rainforest if the sea is shut: Khao Sok.
What the southwest monsoon actually does here
From roughly May to October the Andaman takes the southwest monsoon on the chin: swell, cancelled longtails, and Mu Ko Similan closed ~16 May–14 October 2026. Phuket and Krabi still have hotels; they do not have the postcard water every day. The Gulf side of the peninsula is the swimming hedge in those months. Which coast, Snorkel or dive.
High season (November–April) is the opposite problem: boats and viewpoint queues. Book Similan days early; operators cite a park cap. Foreigner adult park fee is about 500 THB on top of the boat. Cash at the pier.
Karst cliffs look the same in a brochure as they do from a longtail. The difference is whether the crew runs a last boat you can actually catch. Miss it and you are camping without a booking.
Next
Which coast, Best beaches, Snorkel or dive, Park permits, Phuket.