Foreign nationals visiting Thailand must possess valid passports or accepted travel documents and appropriate visas before entering the country. Visitors from certain countries are permitted to stay up to 15 days without visas, provided they possess tickets confirming departure within 15 days, while visitors from several other countries are allowed to apply for tourists visas at all ports of entry. Transit visas are granted for up to 30 days and tourist visas for up to 60 days. Non-immigrants, diplomatic and official visas are valid for up to 90 days.