Can I convert my Non-B visa in Thailand if I don't have it when I arrive?

The duration for processing a Non-B visa can vary, so it's advisable to consult with your company about the specifics. If you arrive in Thailand without a Non-B visa, it is possible to convert to a Non-B visa, but this typically depends on your employer's cooperation and involves a comprehensive amount of paperwork. Some users have successfully converted their visas in Thailand but noted that it can be expensive and requires assistance from lawyers.