Do I have to wait for 7 days (or any period of time) before the expiry of my visa exempt to apply for 30 day extension or can the 1900baht 30 day extension be applied for at any time throughout the validity of the 45 day visa exemption. I'm using Chiang Mai Immigration. Thanks
TLDR : Answer Summary
You can apply for a 30-day extension for 1900 baht at Chiang Mai Immigration anytime during your 45-day visa exemption, as long as you have 45 days or less remaining on your current stamp. This means you could potentially apply for the extension immediately after entering Thailand.