The won was quoted at 1,156.0 to the dollar at the conclusion of onshore trade, up 0.1 percent compared with Wednesday's close of 1,156.6.
South Korean shares reversed later in the day as individuals and local institutions' stock selling outweighed foreign investors' purchases.
The Korea Composite Stock Price Index (KOSPI) closed down 0.1 percent at 2,024.17 points.
Offshore investors marked a third buying session and purchased 325.5 billion won ($281.85 million) worth of shares for the day.