I'm going to Thailand on a tourist visa. I'm planning to stay for at least 6 months. After 3 months I need to do a visa run right? When I have crossed the border and go in to Thailand again, for how long I stay then? If I'm staying for 7 months then I have to do the visa run 2 times right? How many times can I do a visa run? From Phuket where is the easiest way to cross the border? How much does it cost?

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A single entry tourist visa allows a stay of 60 days. You can extend another 30 days by payment of 1,900 baht. Crossing the border and return only provides a 30 day entry without visa stamp. You can cross border/return to Burma or Malaysia (Malaysia also has consulates that could issue a new tourist visa).

What you need is a double entry tourist visa from your local Thai Embassy/Consulate...........this will give you and initial stay of 60 days upon arrival in Thailand which can be extended by 30 days at local immigration (fee 1900 baht) then you do the visa run and re-enter using the 2nd entry on the tourist visa this will give you another 60 days stay which can be extended by 30 days locally once again.

For the 7th month you can simply do another visa run and re-enter and obtain a 30 day on arrival stamp (free)..........assuming you come from one of the qualifying countries.

If you do not come from a qualifying country then you will need to apply for a triple entry tourist visa before leaving home.

I/m not in Phuket so cannot help you with the easiest visa run/cost question.