The surplus was nearly double the $6.52 billion recorded in August and stands as the third-largest September figure on record.
Outbound shipments rose 9.9 percent from a year earlier to $61.67 billion, extending gains for the 12th straight month, while imports increased 4.9 percent over the cited period to $51 billion, according to the central bank's data.
The service account deficit narrowed to $2.24 billion from $3.21 billion a year earlier, while the primary income account surplus expanded to $3.09 billion from $1.69 billion in August, primarily due to reduced dividend payments to foreign investors.
