Thailand Guide
Entry requirements
Extensions and re-entry permits
It's generally easy to get a new fifteen-day tourist visa exemption by hopping across the border into a neighbouring country and back. Such tourist visa exemptions can be extended within Thailand for up to a further ten days, sixty-day tourist visas for a further thirty days, at the discretion of immigration officials; extensions cost B1900 and are issued over the counter at immigration offices ( 
www.immigration.go.th ) in nearly every provincial capital – most offices ask for one or two photos as well, plus two photocopies of the main pages of your passport including your Thai arrival card, arrival stamp and visa. Many Khao San tour agents offer to get your visa extension for you, but beware: some are reportedly faking the stamps, which could get you into serious trouble. Immigration offices in Bangkok and at Suvarnabhumi Airport, as well as at border checkpoints, also issue re-entry permits (B1000 single re-entry, B3800 multiple) if you want to leave the country and come back again while maintaining the validity of your existing visa.