For short trips to Thailand a visa is non-essential. Residents of at least 40 countries can travel to Thailand without a visa. You just need a valid passport or travel documents who are valid not less than 6 months and a return flight ticket. Citizens of New Zealand, Australia, Canada, USA and most European countries can visit Thailand up to 30 days without a visa. These Thailand visa waivers are issued when you arrive in Thailand. For people who enter Thailand by land the 30 days visa can be refused, however: the Thai visa waiver was reduced to 15 days for those who arrive in Thailand by land after January 1, 2009.
If you are not a member of a country that makes a visa free stay in Thailand possible or if you plan a stay longer than 15/30 days, then you need a Thai visa. Visa applications can be done at an embassy or consulate outside of Thailand. Thai tourist visa are valid 30 or 60 days. There is also the possibility to apply for several consecutive 30 or 60 days visa. That makes sense for travellers who are leaving Thailand and come back again. Maximum 3 Thai visa can be issued at one time, allowing the visitor a stay of 30 or 60 days for each entry into Thailand. You have to leave the country within 60 days to be able to use the second 60 days visa.
The penalty for staying more than allowed is 500 Baht per day. Fines can be paid at the airport when leaving. If you stay only one day longer than possible, you don't have to pay any fine or you have to pay 1.000 Baht. Children under 14 years who are travelling with their parents or a guardian don't have to pay any fines for overstays. There are possibilities to avoid overstay fines. Therefore you can visit a Thai immigration office and extend your visa. The visa extension costs are 2.000 Baht. The length of the visa extension depends on your existing Thai visa. Normally 30 days visa can be extended for 7 more days and 60 days visa for 30 more days.
Please note that Thai visa requirements can change anytime. Concerning this matter a Thai embassy keeps you always up to date. Below you will find links to Thai embassy or consulate in: USA, Canada, England, Singapore and Australia.
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