Tourist and Business visas are not required for citizens of the United States for a stay up to 90 days. However, your passport must have at least one blank visa page and be valid for six months. If your passport is expiring or you need to have additional pages added you can view the requirements here.
Fast Passports & Visas always recommends checking with your airline as requirements may change without notice.
South Korea requires that citizens of most countries obtain a visa to enter.  The South Korean Consulate General will determine the duration of stay upon receiving an application.
Business: The South Korean business visa is designed to allow business travelers to come to South Korea in order to pursue business activities, such as attending meetings and conferences.  However, it excludes holders from seeking employment in South Korea.
Tourist:  The tourist visa (also known as the ‘visitor visa’ or ‘visit visa’) allows the holder entry to South Korea, but strictly forbids them from engaging in any work while they are in South Korea.  South Korean tourist visa holders are also not allowed to extend their stay beyond the limits of the visa.