The country's trade surplus came to $6.6 billion last month, down sharply from a surplus of $10.3 billion tallied a month earlier, according to the data from the Korea Customs Service.
Asia's fourth-largest economy has posted a monthly trade surplus since February 2012.
It logged $5.7 billion in trade surplus with Southeast Asian countries in August, including a surplus with Vietnam worth $2.2 billion, while it posted an excess of $3.8 billion in trade with China, its largest trading partner.
Trade with the United States recorded a surplus of $1.4 billion, up slightly from $1.2 billion tallied a year ago, amid the Seoul government's efforts to reduce the goods trade imbalance with the world's largest economy.
The country's exports have been on a roll since November last year on the back of growing overseas demand for Korean-made semiconductors, petrochemical products and vehicles.
In August, exports jumped 17.3 percent on-year to $47.1 billion, while imports also rose 15.3 percent on-year to $40.5 billion. (Yonhap)