The duty comes from section 37 of the Immigration Act B.E. 2522 (1979) and applies to almost every long-stay visa, including retirement visas, the Destination Thailand Visa and Thailand Privilege. Owning property gives no exemption.
The report can be filed in person, through an agent, by post or online, from 15 days before the due date to 7 days after it. Filing late brings a fine of THB 2,000. Leaving Thailand resets the count, which restarts on re-entry. The report is not a visa extension and does not change your permitted stay.
Holders of the Long-Term Resident visa report once a year instead.
Property owners should know about a separate rule, the TM.30. The owner or occupier of a dwelling where a foreigner stays must notify Immigration within 24 hours of arrival. If you let your property to foreign tenants or have foreign guests to stay, that duty falls on you or your managing agent.
