TL;DR:TM30 is the landlord/householder notification to Thai immigration of a foreigner’s residential address (usually within 24 hours) for administrative and security tracking.
The TM30 is a mandatory notification that tells Thai immigration where a foreigner is staying. Under Section 38 of Thailand’s 1979 Immigration Act, the landlord/householder or accommodation operator must report the foreign national’s address to immigration—normally within 24 hours of the foreigner’s arrival. The purpose is administrative and security‑related: it keeps immigration records up to date, helps authorities locate non‑Thai residents when required, and distinguishes hotel reporting (handled by hotels) from private rentals. Reporting can be done in person at the local immigration office, via the Immigration Bureau’s online system or apps, or by the accommodation provider. Failure to submit a TM30 can expose the responsible person (landlord/householder) to fines or other penalties. For official details see the Thai Immigration Bureau guidance and embassy summaries (Thai Embassy and Immigration Bureau pages).
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