Requirements for obtaining a visit visa for South Korea vary depending on your nationality. Foreign nationals entering South Korea are required to have a valid passport and a Korean visa issued by the Korean embassy or consular offices in their country. However, citizens from many countries are now permitted visa-free entry for a limited period under certain conditions. In order to check whether you are allowed to enter Korea without visa issuance and for other requirements, please contact a Korean embassy or consular office in your country or visit the following websites to confirm: Korea Visa Information.

Countries under Visa Waiver Agreement
The 104 countries listed on the website linked below, in addition to Mozambique, which was added in February 2017, are under a Visa Waiver Agreement with South Korea. Depending on nationality and passport type, citizens from these 105 countries can visit Korea with the purpose of tourism without a visa for 30 to 90 days.

Hi Korea (Korean, English, Japanese, Chinese)
For detailed information about visa requirements,
Ministry of Foreign Affairs (Korean, English)
Korea Immigration Service (Korean, English)