What are the rules and procedures for submitting 90-day reports in Thailand?

90 DAY REPORTS (TM.47 form)

I'm going to post this here to help some people I've noticed getting into difficulties:

The first report you make after entering the country must be done *in person* at the immigration office in the province you live in.

EDIT: Steve Smythe who commented below is right (thank you Steve!). You can also submit the first TM.47 90 days after entering Thailand by mail (Thai Post). Personally, I wouldn't recommend this due to reliability issues and particularly not the first ever TM.47 as you might fill it out wrong or not provide the right documents. Details here:

[members only]

Take your passport with you and *make paper copies of the passport pages (face and details) and of the visa page*. You can do this at the immigration office, but it's quicker if you have them ready.

The standard deadlines are: two weeks before and up to one week after the arrival stamp or 90 day period. If you do it too early, it will normally be rejected. If you do it too late, you may have to pay a fine which should be 1,900 Baht - unless you forget completely, then it could be higher.

Subsequent 90 days reports can be done online here (requires registration):

[members only]

When you leave the country and re-enter, the clock is "reset", i.e. do the first 90 day report after re-entering in person and so on.