Visas are now required by almost all visitors to Kenya, including Europeans, Australians, New Zealanders, Americans and Canadians, although citizens from a few smaller Commonwealth countries are exempt. Visas are valid for three months from the date of entry and can be obtained upon arrival at Jomo Kenyatta International Airport in Nairobi for USD$ 50.00 for a single-entry visa, double for multiple entries. Visas are also easily obtained at land crossings with Ethiopia, Tanzania and Uganda. Tourist visas can be extended for a further three month period, but not seven-day transit visas.

It's also possible to get visas from Kenyan diplomatic missions overseas, but you should apply well in advance, especially if you're doing it by mail.