How many times can a Taiwan passport holder obtain a 15-day visa on arrival in Thailand, and can it be extended or converted to another visa type?

A Taiwan passport holder can obtain a 15-day visa on arrival without a strict limit, but frequent use may raise questions at immigration. Generally, this visa type does not qualify for extensions, and as of August 24th, 2022, COVID-related extensions are no longer available. While there are options to convert to another visa type in Thailand, this usually requires having at least 14-21 days remaining on the current visa, which is not possible with a 15-day visa on arrival.