How can I obtain a re-entry visa in Chiang Mai if the immigration office is closed on weekends?

To obtain a re-entry visa in Chiang Mai when you need it before a weekend flight, you can purchase it in advance from the immigration office, which is only open Monday to Friday. Alternatively, you can acquire a re-entry permit at the airport the day before your flight. The re-entry permit is not a visa but allows you to maintain your visa status when leaving Thailand. Keep in mind the costs: 1000 THB for a single entry and 3800 THB for a multiple entry.