Although South Korea's 2008 entry into the United States' "Visa Waiver" program allows for visa-free business stays of under 90 days, you must obtain a visa if you plan to seek employment with a Korean company. The "C-4" visa, for example, permits short-term employment, such as if you plan to teach English in Korea for one of the country's "Summer Camp Sessions." If you plan to teach for a longer term, you must obtain an "E-2" visa, which permits employments in one-year increments. "E-5" and "E-7" visas, on other hand, are available for non-teaching occupations intended to last longer than 90 days.
Students who wish to study in South Korea must obtain a visa prior to entering the country. The Embassy of the Republic of Korea offers two types of student visas: the "D-2" visa and the "E-3" visa. The D-2 is the more generic of the two and is intended for undergraduate, graduate and doctoral students who plan only to study in South Korea. Conversely, the "E-3" visa is designed for academic researchers--student and otherwise--who plan to perform lab studies within Korea.
Foreign diplomats and other officials must also obtain special visas to enter and conduct official business in Korea. The "A-1" visa, for example, is designed for those with diplomatic passports and permits these individuals to engage in diplomacy while in Korea. The "A-2" visa is similar in scope, but applicable to a wider range of foreign officials rather than just diplomats.
