A visa (short for the Latin carta visa, lit. "the document has been seen") is a document issued by a country giving a certain individual permission to enter the country for a given period of time. Many countries require possession of a valid visa as a condition of entry. Visas can be granted on arrival, usually only to citizens of countries enjoying good relations with the issuing country, or by prior application at the country's embassy or consulate. A fee may be charged for issuing a visa; these are typically reciprocal, so if country A charges country B's citizens 50 USD for a visa, country B will often also charge the same amount for country A's visitors. Expedited processing of the visa application will also incur additional charges. Visas are typically stamped or attached into the recipient's passport.

Common types of visas are:

  • transit visa, usually valid for 3 days or less, for passing through the country to a third destination
  • tourist visa, for a limited period of leisure travel, no business activities allowed. Typically the only visa granted for free. Some countries (eg. Saudi Arabia and Kuwait) do not issue tourist visas, although Saudi Arabia does issue pilgrimage visas for Hajj pilgrims.
  • business visa, for engaging in commerce in the country, usually valid longer and more easily renewable than a tourist visa
  • diplomatic visa, which confers diplomatic status on its holder and is normally only available to owners of diplomatic passports

Visas can also be single-entry, which means the visa is cancelled as soon as the holder leaves the country, or multiple-entry, permitting multiple entries into the country with the same visa. Countries may also issue re-entry permits that allow temporarily leaving the country without invalidating the visa. Even a business visa will normally not allow the holder to work in the host country without an additional work permit.

Once issued, a visa will typically have to used within a certain period of time, and the period of validity starts only on entry into the country. A notable exception to this is China, where the visa validity period starts immediately when the visa is issued. Once in the country, the validity period of a visa can often be extended for a fee. Overstaying a visa's validity period is considered illegal immigration and the offender may be fined, deported and even blacklisted from entering the country again.