Lesson of the day
OVERSTAY
First let's start off by saying overstaying your permission to stay stamp ANY length of time is against the law, period, end of story.
It is NOT something to be taken lightly or to treat with a cavilier attitude. You are totally breaking thai law by overstaying.
However with that being said I'd guess that hundreds of people overstay every week :O . Most have short overstays because they don't understand that a 30 day visa exempt entry is for 29 actual days :O (the day you arrive no matter what time is day ONE).
On March 20, 2016 they implemented overstay penalties that banned people who overstayed. The time you are banned varies depending on whether you turn yourself in (at the immigration office, the airport or a land border) OR whether you get caught out on overstay by the authorities.
IF you are turning yourself in with an overstay of under 90 days you are not banned and simply pay the overstay fine, get the stamp in your passport and exit the country.
However if you are caught out on an overstay of even one single day you CAN be banned from the country for 5 years.
Overstay fines are 500baht a day for 40 days then they cap out at 20K baht.
As a rule people on a single days overstay who are flying out will have the 500 baht fine waived and only get a small stamp next to their departure stamp saying "overstay under 24 hours fine waived", however exiting by a land crossing on any overstay always gets the fine.
At this time having an overstay stamp in your passport is NOT a negative thing as far as re-entering the country or getting a visa to thailand at any thai consulate OTHER than Penang which will not issue a tourist visa to people with an overstay stamp in their passport.
The moral of the lesson is DO NOT OVERSTAY, and if you do, do NOT get caught out inside the country while on overstay. <- That is what usually throws people off the rails big time.
Good Luck
TLDR : Answer Summary
Overstaying your permitted stay in Thailand, even by one day, is illegal and can lead to severe consequences. The penalties for overstaying include fines of 500 baht per day, up to a maximum of 20,000 baht after 40 days. If caught during an overstay, individuals can face a 5-year ban from re-entering Thailand, while voluntarily reporting an overstay of under 90 days may only incur fines without a ban. It's crucial for expats to track their visa durations accurately to avoid overstaying.
