If you travel to a foreign country enroute to an overseas destination,
you may need to obtain a transit visa. Each country determines the
criteria which make a transit visa necessary or not. An exception to
this is when you are in transit in a country for which U.S. citizens
are not required to obtain a visa to enter. Most countries allow
foreign citizens to remain in transit for 24 to 48 hours without the
need to get a transit visa as long as they remain in the airport. Stays
longer than this period of time or leaving the airport for whatever
reason could oblige you to apply for a transit visa.
Transit Visa Application and Other Required Documents
The first step is to complete the appropriate visa application form. Most countries provide only one visa application form for all types of visas. Others have a specific application for each type. Some application forms need to be downloaded and printed while others are in electronic format. You need to follow the directions provided by the consular services of the country to which you are making application.
Some countries require the completion of a supplemental visa application in order to provide more detailed information about your travel plans. For example, the United States requires for all male applicants between 16-45 years of age and all applicants from state sponsors of terrorism age 16 and over, irrespective of gender, without exception to complete such a form. A current, valid passport must be presented as well. Many countries require your passport to have a validity date at least six months beyond the your intended period of stay in the country of transit. Finally, a current photograph must be sent in along with the application.