YourThaiPlanet.com

A Border run / Visa run is a slang term invented by ex-pats that means to exit and re-enter the country in order to renew your visa, usually very near the time that your current visa is about to expire. Some have a Thai consulate or embassy that can issue you a new tourist or nonimmigrant visa into Thailand. Others are simply border posts with an immigration station where you can get a 30-day visa-on-arrival, or else a 90 day re-entry visa for those on a non-immigrant business multiple entry visa.