Can I do a re-entry permit at the airport on the day of my flight and how long will it take?

Yes, you can obtain a re-entry permit on the day you fly at an international airport, such as Suvarnabhumi. However, the processing time may vary, typically taking around 20 minutes, depending on the queue. It is noted that some airports may only issue a single re-entry permit rather than a multiple one. For ease, consider visiting an immigration office days prior to your flight.