Other than Indian nationals, and Bangladeshi nationals, all visitors to Bhutan require a visa. Bhutanese visas are issued only from Thimphu.
Further, visas are only issued to tourists booked with a local licensed tour operator. Applications for tourist visas are processed by the tour operator on behalf of their tourist. Visa clearance from Thimphu must be obtained before coming to Bhutan. Visa clearance takes at least 10 days to process. Air tickets to Bhutan cannot be purchased without visa clearance. At your point of entry the visa will be stamped in your passport on payment of US$20, two passport photos will also be required. Visas are issued for a 15 day period. Extensions can be obtained in Thimphu at a cost of Nu. 510.