What happens if you stay longer than your stamp allows — fines, bans, and the immigration process.
500 THB per day overstay up to 20,000 THB maximum; paid at the airport when leaving; must be paid before you can board your flight.
Overstays of more than 90 days result in a ban — 1–10 years depending on duration; the blacklist is taken seriously and enforced at re-entry.
If caught inside Thailand by immigration officials, you will be arrested and held pending deportation — much worse outcome than overstaying and leaving voluntarily.
Pay the fine at the airport; be honest on the departure card; short overstays (a day or two) with the fine paid rarely cause further issues.
