Thailand’s shape is often described as an elephant’s head: a mountainous north and a wide central belt form the head, and the southern peninsula runs south as the trunk. What that means for a trip is that terrain, climate and travel style all change with latitude, not with which coast you pick.
Four regions, one country
The Tourism Authority of Thailand splits the country into five zones that are usually grouped into four for travel planning. The north is mountainous, with cooler winters and the country’s highest terrain around Chiang Mai. The central region is the Chao Phraya floodplain, Thailand’s rice bowl and the seat of Bangkok. The northeast, the Khorat Plateau, borders Laos along the Mekong and averages around 185 m elevation, a dry, undulating tableland rather than a plain. The south is the narrow peninsula between the Andaman Sea and the Gulf of Thailand, the source of most of the country’s beach and island trips.
Overall, Thailand covers 513,120 km², and its coastline runs to 2,815 km split between the Gulf and the Andaman side.
The northern mountains
The forested ranges along the border with Myanmar rise as they run north, culminating in Doi Inthanon, Thailand’s highest point at 2,565 m, in Chiang Mai province. The altitude brings a noticeably cooler climate than the rest of the country, which is why the hill towns and trekking routes around Chiang Mai and Chiang Rai draw visitors escaping the heat of the plains. Trails range from short walks to multi-day treks through hill-tribe villages, and mountain biking is common on the lower slopes.
The central plains and the Khorat Plateau
South of the mountains, the land flattens into the Chao Phraya basin, a wet-rice landscape crossed by the river that gives Bangkok its canals and its position as a river port. East of the central plains, the Khorat Plateau is a different kind of interior: drier, red-soiled, and edged by the Mekong, which forms the border with Laos. It is less visited than the north or south but holds some of the country’s oldest archaeological sites.
National parks and forest
Protected land carries most of what is left of Thailand’s forest away from farmland. Forest cover was 38.69% of land area in 2023, and the national park system, run by the Department of National Parks, Wildlife and Plant Conservation, counted 155 national parks nationwide as of July 2023. The first of them, Khao Yai, was established in 1962 and covers 2,166 km² of forest and grassland a few hours from Bangkok; it remains one of the most accessible places to see wild elephants and gibbons. Further north, the parks around Chiang Mai and Chiang Rai combine forest with the mountain terrain described above.
The two coasts
The Gulf of Thailand side, from Pattaya down to Koh Samui and Koh Phangan, is calmer and more sheltered, which suits family beaches and year-round diving. The Andaman side, from Phuket and Krabi down to the Similan and Surin islands, is more exposed to the open sea and carries the brunt of the southwest monsoon. That exposure is also why it has the better-known reefs and drop-offs. Inland from both coasts, limestone karst outcrops, at their most dramatic around Krabi and Phang Nga Bay, are the result of the same geology that gives the region its caves and sea cliffs.
What to check before you go
- The Andaman coast’s outer islands close for the monsoon: Similan and Surin national parks shut from 15 May to 15 October each year for safety and reef recovery, so boat trips and overnight stays there are unavailable in that window.
- Mountain routes around Chiang Mai and Chiang Rai get noticeably cold at night in the December–January cool season; pack accordingly if you are trekking at altitude.
- National park entry and opening status change with the season and with local conditions; check the park’s status before planning a day trip, especially outside the main dry season.