Does a Non-B visa become invalid when the work permit expires, and will there be a fine for overstaying?

Just an FYI: for anyone on a year-long, multi-entry Non-B visa.

It does not matter if you quit your job and cancel your work permit when you are on this type of visa. You are free to stay 90 days at a time for the validity of the visa no matter if you're working or not.

@Evgeny *******

, you are on a VISA (not an extension) and that means you can continue to coming in and out of the country on that visa until the "enter before" date. If you exit/re-enter just before Sept 26th 2018 you would get stamped in for 90 more days.

Unfortunately you CANNOT turn the visa you have into a year long extension of stay based on retirement and you can't switch to a 90 day Non-O visa inside the country from it either.

you can get as much time out of this visa you have as you can but then you will either need to go get a 30 day visa exempt entry or a single entry tourist visa and convert that to a 90 day Non-O at the immigration office

OR

Once you get as much time out of this visa as you can you can go to a thai consulate and buy a 90 day single entry Non-O visa

I have a similar situation coming up. My work permit runs until September and I will be leaving my current role when that time comes. However my non b is valid until November.

Do I have to leave in September or can I stay until November?

I have been doing a border bounce every 90 days so far (first year having a non b).

Thanks

If you have a valid Non Immigrant B visa and doing every 90 days a border run, this visa stays valid. If you're on the Extension of Stay based on working and doing 90 days reports at Immigration you must cancel this the same date as the day your stop working.