After the meeting, Sihasak Phuangketkeow, Permanent Secretary for Foreign Affairs who is acting Thai foreign minister, said the countries endorsed the first action plan for their cooperation in the next three years.
The cooperation will cover infrastructure, technology, agriculture, rural development, water resources, environmentally friendly growth and human resource development among others.
Mr Sihasak said that it created investment opportunities in the Mekong River Basin and under the cooperation Thailand and South Korea would offer assistance to the rest of the countries.
Thailand is training their officials and developing their local communities and roads including Route 48 from Koh Kong to Sre Ambel in Cambodia and a road from Mae Sot district of Thailand via Myawaddy to Kaw Kareik in Myanmar.
He said they would be important economic routes.
"It is an opportunity to boost economic cooperation between South Korea and countries in the Mekong River Basin, narrow economic gaps among ASEAN countries and help speed up the formation of the ASEAN Community," Mr Sihasak said.
He also said that South Korea is interested in developing Route 48.