How many times can I enter Thailand on a visa on arrival each year?

There is no official limit to the number of times you can enter Thailand using a visa on arrival (VOA) per year. The decision is ultimately at the discretion of the immigration officer at the point of entry. It's noted that while you can use the visa on arrival multiple times, you must also be cautious of any suspicions from immigration regarding your intent to reside in Thailand without a proper visa. In case of back-to-back entries on a visa on arrival, it's advisable to have documentation, such as proof of upcoming visa appointments, to present at entry.