This is a secure permit launched only in Tibet Autonomous Region which the government to adjust a better ways for touring stability. Tibet travel permit is being issued by Tibet tourism bureau about 25 days prior to your arrival date.
Tibet travel permit has four kinds: Tibet tourism bureau permit (TTB), military permit, foreign affair permit and public security bureau(PSB) permit. This permits distribute to agent in the last 3 to 7 days. These permits are no longer eligible for personals except contacting a local travel agency in Lhasa to get it. To avoid the burden process like urgent handles, please confirm your tour prior 20 days you enter Tibet.
Independent travelers are currently not allowed in Tibet Autonomous Region. Instead you can also book a tour to Amdo and Kham regions which are not equally valuable as were the previous provinces of Tibet. Non of them need Tibet travel permit.