Trick question, "When does 90 days not mean 90 Days - Batman?

I would like to pass on my own experience at Phuket Immigration in Phuket town last week - for sure other regional offices maybe applying/enforcing different rules.

Something I was not aware of, and only through the good fortune of the Farang volunteers working there, did they pointed out something that I was unaware of, which hopefully might be of help to others:

When your visa is about to expire, your 90 day reporting will only be valid up until the date it expires.

This was actually confirmed to me on the reporting slip of paper that the Immigration had previously provided me, sure enough it was stamped and stated that my 90 day report expired on the same date my visa expires.

That may be police in Phuket but it is not the law or policy in other locations, such as Bangkok. Only the first extension of stay has any effect on 90 day reporting (start date).

Maybe that's why my local Imm office reset my 90 day report from the day I get my extension!

It happened to me last year in Chiang Mai. My extension was up in about 6 weeks and went in for 90 day report. It was stamped up to the extension expiration and an additional stamp reflecting my extension expiration. When I went in for the 1 year extension renewal, the officer dealing with my extension just stamped my 90 day report out to where it would normally be and didn't have to queue up again.

However, my extension is up in 3 weeks and went in two weeks ago for the 90 day and got the full 90 day and a stamp reminding my of my extension expiration. They're consistent at being non-consistent.

It happened to me last year, my 90-day report was limited to 60 days to coincide with the expiry date of my visa. It has happened again this year although I was given an extra 28 days (118 days) - this also coincides with the expiry date of my visa extension. It is a helpful measure and saves an unnecessary trip for the 90-day report. (Korat Immigration).