Foreigners wanting to enter Korea have to be in possession of a valid passport and a visa issued by a Korean embassy or consulate. However, in the following cases, it is also possible to enter the country without a visa:

– In possession of a permission for re-entry and returning to Korea before its expiration
date;
– Citizen of a country having a visa waiver agreement with Korea, and thus according to
the agreement being exempt from a visa;
– Working for a foreign government or an international organization and without a visa due to unforeseen circumstances;
– Purpose of travel or transit;
– Other reasons determined by the Minister of Justice where the entry to the country will
bring benefits to Korea.

Regarding the visa waiver agreement, it is in principle limited to foreigners for the purpose of short-term travel or visit (less than three months) without conducting profit-making business or any paid activities.
As of end of April 2004, there are a total of 78 countries having concluded a visa waiver agreement with the Korean government including the United Kingdom, France, Germany, Singapore and New Zealand. Citizens from these countries receive a B-1 visa waiver with a specific period of sojourn (usually 3 months).Countries with visa-free entry permission to Korea as of April 2004 totaled 50 countries, including the USA, Canada, Japan, and Australia. If citizens from these countries wish to enter the Republic of Korea for the purpose of travel or transit, they will be issued a B-2 visa with a sojourn period of 30 days. However, citizens of Canada are allowed 6 months, and citizens of Australia, Hong Kong and Slovenia are allowed 90 days sojourn (based on reciprocity).Citizens from countries, with which no diplomatic have yet been established, such as Cuba and Macedonia, as well as citizens of countries with many illegal entries to Korea, such as China, Mongolia, the Philippines, Nepal and Nigeria are not allowed entry without a visa.