Can you extend a Thai tourist visa twice without doing a border run?

The only other available extension would be if you had Thai family (wife or child)

Your visa exempt entry(30 days) cannot be extended more than once, same for the tourist visa(60 days). Your only choice is to leave the country and enter again under a new entry stamp

Tourism extension is available only ONCE for one entry on tourism status, on visa-exempt or Tourist Visa.

If you apply for a second tourism extension, it will be denied and you will be stamped for 7 days to leave the country. Unless you have a specific reason, we don't recommend getting this stamp especially if you are seeing border-bounce by land. Some borders wouldn't let you bounce in with this stamp for the last entry.

you didn't get any visa when you came in (there is no 30 day tourist visa 😕 ) you showed up and were stamped in free for 30 days.

you can get ONE 30 day extension from that free entry stamp and then you're done. So seeing as you already got the one 30 day extension you're allowed IF you wan to stay longer you need to exit the country and re-enter on a new entry stamp.

Those 30 day extensions on either a free entry stamp or a tourist visa are "one-&-done" sort of things, can't get more on the same entry..