The Southern Economic Corridor (SEC) is a part of the economic corridor approach adopted by the Mekong Subregion countries in 1998 to help accelerate the pace of sub-regional economic cooperation. The role of the SEC is to link the sub-region to major markets and nodal points within these economic corridors to serve as centers for enterprise development. SEC encompasses four ASEAN countries namely Cambodia, Myanmar, Thailand and Vietnam (CMTV). The SEC is comprised of the sub corridors and inter corridor indicated as follows:
- Bangkok – Phnom Penh – Ho Chi Minh City – Vung Tau Sub-Corridor (Central Sub-Corridor);
- Bangkok–Siem Reap – Stung Treng – Rathanakiri – O Yadov – Pleiku – Quy Nhon Sub-Corridor (Northern Sub-Corridor);
- Dawei – Bangkok – Trat – Koh Kong – Kampot – Ha Tien – Ca Mau – Nam Can Sub-Corridor (Southern Coastal Sub-Corridor);
- Sihanoukville – Phnom Penh – Kratie – Stung Treng – Dong Kralor (Tra Pang Kriel) – Pakse – Savannakhet Inter-Corridor Link, which links the three SEC sub-Corridors with the East–West Economic Corridor (EWEC)
The importance of the SEC has risen in the recent years due to the Dawei Development Project in Myanmar. The project is expected to result in increase in the volume of trade and investment along the SEC and the Corridor has the potential to be developed as the most important corridor in the ASEAN Mekong Subregion (AMS).