Is it common for Thai Immigration to require a same-day bank letter for extending a Non-Resident O visa?

The process of extending a Non-Resident O visa in Thailand may vary significantly depending on the specific Immigration office. Many users reported that some offices require the bank letter to be dated the same day as the extension application, while others accept letters issued several days prior. Locations such as Rayong, Buriram, and Kanchanaburi follow the same-day policy, whereas cities like Bangkok and Chiang Mai may allow for letters dated up to a week before the application. It's advisable to consult directly with the local Immigration office for precise requirements.