US passport here 30 days exempt in Chiang Mai. I want to extend my stay at the Central Festival office. My hotel says I should wait until later on in my 30, but would like to do it ASAP. Thanks
TLDR : Answer Summary
A US passport holder can extend their 30-day exempt stay in Chiang Mai anytime during the first 30 days. It's recommended to do so at the Central Festival office. However, avoid visiting on Mondays and Fridays, as these are the busiest days. Additionally, ensure that a TM30 address registration is on file with Thai Immigration before applying for the extension, and be prepared to pay around 1900 Thai baht for the extension.