Do hotels in Bangkok file immigration paperwork for foreign guests, and what are the TM30 requirements when returning to Koh Tao?

Wayne Ellis. The TM30 is basically what Thai immigration use to locate any visitor ("alien") in Thailand. It is linked to your passport number and your TM6 form, which is the one you fill in when you arrive in the country, the stub of which remains in your passport. Hotels will in most cases register your details with immigration when you check in. You can request a screenshot of the registration wherever you are, although it's not always necessary, but could be if you're staying in a location for a while and will do your 90-day report (which is another method of immigration keeping tabs on your movements). Where the TM30 system can fall down is with landlords who don't bother to register you, and leaves it up to you to file your own TM30, which can be a nuisance.