South Korea's exports surged 78 per cent from a year earlier in the first 20 days of September, customs data showed on Monday, driven by strong shipments of semiconductors.

Outbound shipments reached $71.4 billion in the September 1-20 period, soaring from $40 billion posted in the same period in 2025, according to the data from the Korea Customs Service, reports Yonhap news agency.

It marked the highest volume for the 20-day tally, with the previous record standing at $61.7 billion posted in June this year.

Imports went up 26.7 percent on-year to $48.4 billion over the cited period, resulting in a trade surplus of $23 billion.

By product, exports of chips shot up 259 percent to reach $34.12 billion.

Exports of petroleum products and cars went up 47.8 percent and 9.3 percent, respectively, to $4 billion and $3.73 billion.

Other major winners included steel products and ships, whose exports increased 8 percent and 63 percent, respectively.

Exports of mobile devices, on the other hand, shed 0.4 percent to $1.24 billion.

By destination, exports to China more than doubled to $16.6 billion, with those to the United States also surging 118 percent to $14.2 billion.

The accumulated exports through Sunday this year, meanwhile, came to $764.9 billion, with the trade surplus reaching $225.5 billion.

Meanwhile, Seoul stocks were trading higher late on Monday morning as gains in major chipmakers lifted the broader market, offsetting concerns over Middle East tensions and elevated oil prices.

The benchmark Korea Composite Stock Price Index (KOSPI) added 106.65 points, or 1.55 percent, to 7,000.88 as of 11:20 am.

U.S. semiconductor shares rallied Friday, providing a positive cue for major Korean chipmakers.

The Philadelphia Semiconductor Index jumped 2.78 percent, while the tech-heavy Nasdaq gained 0.39 percent and the S&P 500 edged up 0.17 percent.

Elevated crude oil prices remained a concern amid persistent inflationary and geopolitical risks in the Middle East. Brent crude traded at around US$104.68 a barrel.

The Korean won was quoted at 1,386.0 won against the U.S. dollar as of 11:12 a.m., down 0.5 won from the close of the previous stock trading session.