At 06:30 GMT, the KOSPI closed higher 17.08 points or 0.71 percent at 2,436.37. The benchmark index extended gains following gains in Chinese stock markets. Seoul's announcement that South Korea and North Korea agreed to hold summit in April, also cheered market sentiment.
The won was quoted at 1,065.9 per dollar on the onshore settlement platform, 0.46 percent firmer than its previous close at 1,070.8.
In offshore trading, the won was quoted at 1,064.44 per US dollar, down 0.08 percent from the previous day, while in one-year non-deliverable forwards it fetched 1,051.8 per dollar.
MSCI's broadest index of Asia-Pacific shares outside Japan was up 0.28 percent, after US stocks ended the previous session with losses. Japanese stocks rose 0.61 percent.
The KOSPI is down around 2.0 percent so far this year, and down by 2.35 percent in the previous 30 days.
The current price-to-earnings ratio is 12.10, the dividend yield is 1.28 percent and the market capitalisation is 1,242.04 trillion won.
The trading volume during the session on the KOSPI index was 328,140,000 shares, and of the total traded issues of 887, the number of advancing shares was 447.
Foreigners were net sellers of 271,705 million won worth of shares.
The US dollar has fallen 0.18 percent against the won this year. The won's high for the year is 1,056.67 per dollar on January 14 2018 and low is 1,098.4 on February 6 2018.
In money and debt markets, June futures on three-year treasury bonds rose 0.01 points to 107.68.
The Korean 3-month Certificate of Deposit benchmark rate was quoted at 1.65 percent, while the benchmark 3-year Korean treasury bond yielded 2.228 percent, higher than the previous day's 2.22 percent.