What should I do if I received a 90-day stamp when I expected a 30-day entry in Thailand?

Personally what I'd do (no matter where you are in thailand) IS;

Go to Suvarnabhumi airport this weekend (they are open ) get the stamp corrected.

Then show up down there at the Island of Misfit Toyz (aka Koh Phangan) immigration office bright and early monday morning so when they open at 8:30 you can get this overstay cleared and get your extension.

I say that because if you wait until Monday and that office WON'T correct the stamp then you have more overstay fines while you get up here and get the stamp corrected, then go get the extension

Sometimes happens they wrong to set stamp....in my old passport have one date of exit before the date of entry.....from that time always double check!!!!!

You MUST go to Survarnabhumi ASAP get it sorted. You are now on overstay. If they change the stamp they may hold you and deport you as you don’t have an extension.

Crazy but trust Tod..he is an expert

You need to go back and fix it. This is the second one I’ve seen.

7 days overstay already, that's 3500 baht fine so far.

It's a mistake, it's been happening a lot lately. Thing is it's completely your responsibility to check it and have it corrected. Yeah I know.

You need to go back the airport to customer services/ information desk and tell them. They will call an immigration officer to come and correct it for you.

It's called a 'visa exempt' just so you have the correct terminologies when there.

First off your "lawyer" is confused and 100% WRONG 🙁 You're about as far from "all good" as you can throw a stick 😮

Okay, you arrived and were expecting a 30 day visa EXEMPT entry (not a visa on arrival, just a free entry stamp) but sadly for you they stamped you in wrong..

You were only supposed to get a ผ.30 stamp <- 30 day visa exempt

You CANNOT stay the 90 days, and in fact right now you're on overstay since Dec 29th 😮 <- the day your REAL 30 day visa exempt entry would expire..

You need to go back to Suvarnabhumi and get the stamp corrected, THEN you need to high-tail it to the immigration office where you stay (if you're in Bangkok you go to the one at IT Square Laksi Plaza) and apply for the 30 day extension.

IF you can get there Monday you'll get fined for 10 days overstay (500baht a day for 10 days = 5000baht) and then you can get your 30 day extension, which will be dated from the actual date your corrected stamp shows (which will be Dec 29th)

Just so everyone is clear about this, YOU are responsible for checking your passport, making sure you're stamped in correctly and if you're stamped in wrong YOU need to get it corrected and are responsible for any overstay that occurs on that bad stamp.