If foreign national is in Thailand on a one-year non-immigrant visa, they have to report their address in Thailand to Thai immigration. If the foreign national expects to be in Thailand over 90 days, the foreign national must continue to report their current address every 90 days until they leave. The 90 day reporting is still required even if the foreign national has a one year or multiple year entry visa. The 90 days reporting period restarts every time the foreign national reenters Thailand.

Check the thaiembassy.com Doing the 90-day Reporting.

There are three ways to meet the 90 days reporting requirement. The foreign national can notify the Immigration Bureau by appearing in person at a government immigration office. The foreign national can authorize another person to appear that the office for them. Or the foreign national can notify the immigration office by registered mail. A notification by registered mail must be sent to the Immigration Office at least 15 days before the 90 day reporting period.

The 90 day notification is not a visa extension. If the foreign national wants to stay in Thailand beyond their initial period of authorized stay, they will have to apply for a visa extension. If the foreign national fails to file a 90 day reporting, they will face a fine of 2,000 baht. If the foreign national who failed to file a notification is arrested, the fine is 5,000 baht.