Can I Obtain a Thai Visa Extension on the Expiration Date of My 30-Day Exemption?

You can obtain an extension on your 30-day exempt entry in Chiang Mai on the day it expires. Overstay begins the day after the expiration date, so you have the full day to either leave the country or secure an extension. Many users confirm that going on the expiration date is acceptable, and some even mention that they have gone for extensions on the same day they arrived, provided the immigration office is open.