Trade surplus amounted to 6 billion U.S. dollars in September, logging the biggest monthly figure this year, according to Korea Customs Service. The trade balance stayed in the black since February, 2012.
Export diminished 11.7 percent over the year to 44.7 billion U.S. dollars in September, while import reduced 5.6 percent to 38.7 billion U.S. dollars in the month.
Semiconductor export tumbled 31.6 percent on the ongoing downturn of business cycle of the global chip industry, while oil product export declined 18.2 percent amid the cheaper crude oil.
Display panel shipment plunged in double figures, but export for telecommunication devices such as smartphones advanced 81.9 percent. Shipment for automobile and consumer electronics increased last month.
Export to China, South Korea's biggest trading partner, contracted 21.8 percent, with those to the United States and Japan sliding 2.2 percent and 6.0 percent each.
Shipment to the European Union and Vietnam expanded 10.6 percent and 6.5 percent respectively.