How to get the most out of a year-long, multi-entry Non-Immigrant Type O visa.
This type of visa can be issued for a variety of reasons. The most common and widely used is based on marriage to a thai national. This visa is available at SOME thai consulates in year-long, multi-entry and others as only a 90 day single entry.
We are talking about the year-long, multi-entry Non-O in this post and it doesn't matter what reason you used to get it.
The visa is valid for a year from the date it's issued. It is unlimited entry during that year and every entry gets you stamped in for 90 days. You can get 15 months of stay (in 90 day increments) off a visa that is valid for a year this way;
Get the visa, enter thailand on a 90 day stamp
when the stamp is running out, exit/re-enter getting a new 90 day stamp (taking you to about 6 months)
when the stamp is running out, exit/re-enter getting a new 90 day stamp (taking you to about 9 months)
when the stamp is running out, exit/re-enter getting a new 90 day stamp (taking you to about a year) < pay attention to the expiration date on the VISA so you don't mess up the next step
When the VISA itself is running out ,exit/re-enter getting a FINAL 90 day stamp (taking you to almost 15 months).
AND
to maximize the in country time get the 60 day visit family extension at the immigration office for 1900baht on that last 90 day entry. That ends up taking you to 17 months total :P ;) :)