I am here on an extension of stay from a B visa. I have a new job and i am leaving on Saturday morning. Should i cancel the extension or just leave? My employer says just leave as it will be cancelled at the airport.

Best to have canceled at immigration or you might have problems getting another extension later. Some immigration offices have insisted the extension be formally canceled before doing another extension.

If you have a termination letter dated on the day your are leaving or after you can go to immigration and they will post date the cancelation to that date.

Another problem you could have is if you have valid re-entry permit. Immigration could insist on using it when you enter the country again.

I will not be be back in Thailand for 6 - 12 months as the job is in another country. I will ask for a termination letter and get it cancelled.

Thanks.

If you leave without a re-entry permit then your extension is finished, gone.

If/when you return you will get 30 days visa exempt or whatever days allowed if you have a visa.

However if you are on good terms with your employer get a letter confirming your last day of work, get your extension cancelled ( at the office that issued it ) and fly out that night or next day.