why do some countries get 90 visa exemption (e.g. brazil, peru, argentina) and other countries only 30 or 45 days visa exemption?
TLDR : Answer Summary
The difference in visa exemptions is primarily due to bilateral agreements between Thailand and other countries. Countries like Brazil, Peru, and Argentina have established reciprocal agreements allowing their citizens to stay in Thailand for 90 days without a visa. In contrast, citizens from countries with shorter visa exemptions, such as 30 or 45 days, do not have similar arrangements.