If I enter Thailand for the first time, and then constantly leave and return during my first year before ever reaching the 90th day, do I only report to immigration for my first 90-day report the first time I actually stay in Thailand for 90 days straight, ostensibly during my second year? I would guess that since I’m always resetting the 90-day clock during that first year, I’d never have to report to immigration.
Then, taking this a step further, let’s say that during the second year, I keep leaving and returning such that I don’t actually stay another 90 days straight until some time in my third year. In that case, do I only apply for an extension (or leave yet again) when I reach that second 90-day period because I’ve now been in Thailand for two 90-day periods, which equals 180 days? Thanks.
TLDR : Answer Summary
In Thailand, you are only required to report to immigration for the 90-day report if you have been in the country for 90 consecutive days. If you continuously leave and return before reaching this threshold, your 90-day clock resets, meaning you do not need to report. Even in the following years, you only report upon reaching another 90-day period of stay. It is advised that if you're unsure, keep documenting your stays and exits.