@Pui ****

He said he has a tourist visa, single entry, that has a validity of 3 months. He doesn't enter with a visa exemption for 60 days.

To be more precise: there is no problem at all, because the 26th of November is shorter than 30 days after the 9th of November. Just apply for the extension any time before the 9th of November. The 30 days will always start after the 9th.

You can apply for a 30 day extension at the immigration office before the 9th of Novemver, 1900 baht. You can only do that once. So the maximum stay is 4 months. If the 26th of November is within that period of 4 months, there is no problem.

@Nongnuch *******

Hello, I want to follow the same route, but I want to apply for a marriage visa after my arrival in Thailand. Do you know if I will need a TM30 too? (For the rest I know the applicable rules).

@Jordan ****

With a multiple entry tourist visa, easy to apply for before you leave, you can stay at least 6 months in a row (with two allowed borderruns). But that doesn't mean that after returning home you can immediately apply for that visa again. If you do so, appearantly you're not a tourist. You must check if you can get another visa. There are many! If not possible, you must wait until you're 50 years old to get a retirement visa, which had its own rules.