You need a Tibet Entry Permit to enter Tibet

All the foreigners need a Tibet Entry Permit to visit Tibet, and the only way to enter Tibet is only through by travel agency, which helps you to apply Tibet travel permit to enter Tibet.Your whole tour in Tibet must be accompanied by a licensed tour guide.The Tibet Entry Permit is very important. It will be checked at the train station/airport, when you enter attractions in Tibet, and even when you check in to a hotel. So take care of it.