Southeast Asia
Southeast Asia is a maritime and mainland region of Asia comprised of eleven countries. It is a centre of economic growth and biodiversity with bustling cities and pristine islands.
About Southeast Asia
Southeast Asia encompasses a vast archipelagic and peninsular region stretching from Myanmar in the west to the Philippines in the east, and from continental areas bordering China to the Indonesian archipelago extending below the equator. This region is home to over 680 million people and includes both mainland countries (Myanmar, Thailand, Laos, Cambodia, Vietnam) and maritime nations (Indonesia, Malaysia, Singapore, Philippines, Brunei, Timor-Leste).
The region is characterized by tropical climates, dense rainforests, and extraordinary biodiversity, making it one of the world's most ecologically diverse areas. Southeast Asia sits at the crossroads of major trade routes between the Indian and Pacific Oceans, which has shaped its history as a melting pot of cultures, religions, and trading traditions. The region has been influenced by Indian, Chinese, Islamic, and Western civilizations, creating a unique cultural tapestry. The Mekong, Irrawaddy, and Salween rivers all begin far north of the region and run through it on their way to the sea — for the longer story, see rivers of Asia. The diversity of dominant religions across the region (Buddhism in Thailand, Laos, Cambodia, and Myanmar; Islam in Indonesia, Malaysia, and Brunei; Catholic Christianity in the Philippines and Timor-Leste) is mapped in religions of Asia.
Economically, Southeast Asia is one of the fastest-growing regions in the world. Since Timor-Leste joined in October 2025, all eleven countries are members of ASEAN (the Association of Southeast Asian Nations), a regional organisation promoting political, economic and security cooperation. The region is known for its manufacturing industries, agricultural exports (rice, rubber, palm oil), tourism sector, and increasingly, its technology and digital economies. Major cities like Singapore, Bangkok, Jakarta, and Manila serve as important financial and commercial hubs in the global economy.
The region faces both opportunities and challenges, including rapid urbanization, environmental concerns such as deforestation and pollution, natural disasters like typhoons and tsunamis, and the need to balance economic development with cultural preservation and environmental sustainability.
Countries in Southeast Asia
Quick facts: Southeast Asia has 11 countries — five on the mainland and six in maritime (island) Southeast Asia. All 11 are ASEAN members, Timor-Leste having joined on 26 October 2025. Laos is the only landlocked country, and Indonesia is the largest by both area and population.
ASEAN: the 11 member states
The Association of Southeast Asian Nations (ASEAN) was founded on 8 August 1967, when Indonesia, Malaysia, the Philippines, Singapore and Thailand signed the Bangkok Declaration. Brunei joined in 1984, Vietnam in 1995, Laos and Myanmar in 1997 and Cambodia in 1999, bringing membership to ten. On 26 October 2025, at the ASEAN Summit in Kuala Lumpur, Timor-Leste was formally admitted as the 11th member. An "ASEAN map" of the 11 member states and a political map of Southeast Asia therefore now show exactly the same countries.
| Country | Capital | Capital coordinates (lat, lon) | Joined ASEAN |
|---|---|---|---|
| Indonesia | Jakarta | -6.21, 106.85 (6.21°S, 106.85°E) | 1967 |
| Malaysia | Kuala Lumpur | 3.14, 101.69 (3.14°N, 101.69°E) | 1967 |
| Philippines | Manila | 14.60, 120.98 (14.60°N, 120.98°E) | 1967 |
| Singapore | Singapore | 1.29, 103.85 (1.29°N, 103.85°E) | 1967 |
| Thailand | Bangkok | 13.76, 100.50 (13.76°N, 100.50°E) | 1967 |
| Brunei | Bandar Seri Begawan | 4.90, 114.94 (4.90°N, 114.94°E) | 1984 |
| Vietnam | Hanoi | 21.03, 105.85 (21.03°N, 105.85°E) | 1995 |
| Laos | Vientiane | 17.98, 102.63 (17.98°N, 102.63°E) | 1997 |
| Myanmar | Naypyidaw | 19.76, 96.08 (19.76°N, 96.08°E) | 1997 |
| Cambodia | Phnom Penh | 11.56, 104.93 (11.56°N, 104.93°E) | 1999 |
| Timor-Leste | Dili | -8.56, 125.56 (8.56°S, 125.56°E) | 2025 |
Coordinates are for the city centre, rounded to two decimal places (roughly 1 km); negative latitudes are south of the equator. Malaysia's federal government offices are largely in Putrajaya, but Kuala Lumpur remains the official capital. Indonesia is building a new capital, Nusantara, on Borneo, while Jakarta continues to serve as the seat of government. Naypyidaw replaced Yangon as Myanmar's capital in 2005–06. All capitals are listed on the capitals of Asia page.
Mainland and maritime Southeast Asia
Geographers usually split the region in two. Mainland Southeast Asia, also called the Indochinese Peninsula, lies south of China and east of India and is crossed by long north–south rivers such as the Mekong, Chao Phraya and Irrawaddy. Maritime Southeast Asia covers the Malay Archipelago — thousands of islands stretching from Sumatra to the Philippines and Timor — together with Peninsular Malaysia and Singapore, which are usually grouped with it.
Mainland Southeast Asia (5 countries)
Maritime Southeast Asia (6 countries)
Malaysia straddles both halves: Peninsular Malaysia sits on the Malay Peninsula, attached to the mainland, while the states of Sabah and Sarawak lie across the South China Sea on Borneo. It is normally grouped with the maritime countries. Several islands are shared between countries: Borneo is divided between Indonesia, Malaysia and Brunei; Timor between Indonesia and Timor-Leste; and New Guinea between Indonesia and Papua New Guinea.
Why do some Southeast Asian countries look like they have a tail?
On a map of Southeast Asia, Thailand is often compared to an elephant's head with a long trunk, and Myanmar has a thin strip running down its south-eastern edge. Both "tails" follow the Malay Peninsula, the long, narrow arm of land that runs south from the mainland towards Singapore.
- Thailand: the country's southern provinces run down the Malay Peninsula as far as the border with Malaysia. Near Prachuap Khiri Khan, Thailand is only about 11 km wide between the Myanmar border and the Gulf of Thailand.
- Myanmar: the Tanintharyi Region is a narrow coastal strip along the Andaman Sea, separated from Thailand by the Tenasserim Hills. It ends at Kawthaung, near the Kra Isthmus — the narrowest part of the Malay Peninsula, roughly 44 km across.
- Vietnam: a long S-shape squeezed between the Annamite Range and the South China Sea, only about 50 km wide in Quang Binh province.
These shapes are partly historical. Britain took the Tenasserim coast from Burma after the First Anglo-Burmese War (1824–26), leaving the border with Siam (Thailand) along the hills inland, and the 1909 Anglo-Siamese Treaty fixed Siam's southern boundary with British Malaya part-way down the peninsula. You can see each outline in detail on the Thailand, Myanmar and Vietnam maps.
Frequently asked questions
How many countries are in Southeast Asia?
There are 11 countries in Southeast Asia: Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, Timor-Leste and Vietnam.
Are all Southeast Asian countries members of ASEAN?
Yes. Since Timor-Leste was admitted on 26 October 2025, all 11 Southeast Asian countries belong to ASEAN. Papua New Guinea, which shares the island of New Guinea with Indonesia, has been an ASEAN observer since 1976 but is usually counted as part of Oceania rather than Southeast Asia.
Which country is the newest member of ASEAN?
Timor-Leste. It applied for membership in 2011 and was formally admitted as the 11th member state at the ASEAN Summit in Kuala Lumpur on 26 October 2025. Before that, the most recent new member was Cambodia in 1999.
Why do Thailand and Myanmar look like they have a tail on the map?
Both countries extend down the narrow Malay Peninsula. Thailand's southern provinces run south to the Malaysian border, and Myanmar's Tanintharyi Region is a thin coastal strip along the Andaman Sea. The border between them follows the Tenasserim Hills, which is why both "tails" are so long and thin.
Which Southeast Asian country is landlocked?
Laos is the only landlocked country in Southeast Asia. It borders China, Myanmar, Thailand, Cambodia and Vietnam, and the Mekong River forms much of its border with Thailand.
What is the largest country in Southeast Asia?
Indonesia is the largest country in Southeast Asia by both area (about 1.9 million km²) and population (more than 280 million people). Singapore is the smallest by area.