If your work permit expires on, say, the 30th of September, and in your passport it states that you must leave the Kingdom by the 30th of September, is there some type of grace period allowing you to actually fulfill your contract and leave?

It is impossible to work until the 30th (thus fulfilling your contract) and then leave the same day. Surely immigration does not mean this and they give you time to get your affairs in order before having to leave.

What is the rule? Thanks.

If your work permit ends 30 Sep and you are on an extension of stay until 30 Nov you would be allowed 7 days to leave. It appears you may be on a 90 day visa entry? And the work permit date just followed your visa entry date? So you would have had to leave on 30 Sep regardless of continued work or not to obtain a new permitted to stay stamp.

In any case I suspect you can obtain a 7 day extension of stay from Immigration for 1,900 baht - or just make a Cambodia border trip to obtain a 30 day visa exempt entry.

If your work permit ends 30 Sep and you are on an extension of stay until 30 Nov you would be allowed 7 days to leave. It appears you may be on a 90 day visa entry? And the work permit date just followed your visa entry date? So you would have had to leave on 30 Sep regardless of continued work or not to obtain a new permitted to stay stamp.

In any case I suspect you can obtain a 7 day extension of stay from Immigration for 1,900 baht - or just make a Cambodia border trip to obtain a 30 day visa exempt entry.

Thanks.