All travelers into Bhutan should have a valid passport, preferably with at least six months validity is essential. Unusually, visas cannot be obtained at Bhutanese embassies overseas. Instead a visa clearance number has to be obtained by your travel agency through the Ministry of Foreign Affairs, Thimphu and a copy of the visa clearance number will also be automatically intimated to all Druk Air Stations and a copy of the same will be either faxed or emailed to you. Without this visa clearance number the Druk Air will not permit to board the flight. US $ 20 will be charged along with the daily tourist tariff as a visa fee whereby your agent will deposit the same with the Government in order to avoid the hassle for you at the airport on entry.