The 90-day report (TM47), explained

Who has to report

Anyone staying in Thailand for more than 90 consecutive days must notify immigration of their address every 90 days. In practice that's everyone on a long-stay visa or extension: retirement, marriage, education, work, DTV and Thailand Privilege. LTR visa holders report once a year instead.

Visa-exempt visitors and tourists rarely hit 90 continuous days, so it usually doesn't apply to them.

How the 90 days are counted

• The day you arrive is day 1; the report is due on day 90.
• After you report, the next one is due 90 days later.
• Leaving Thailand resets the count. Your next report is 90 days after you come back.

The filing window

You can file from 15 days before the due date until 7 days after it. Miss the window and the fine is 2,000 THB (more if you're caught never having reported).

How to file

• Your first report after arriving must be done in person at your local immigration office.
• From the second report on, you can usually file online at tm47.immigration.go.th, by post, or in person.
• Bring your passport, the TM30 receipt for your address, and your previous 90-day slip.
• Online confirmations usually arrive within 1–3 days. The system checks your address against your TM30, so make sure it's up to date.
• The new THIM immigration app is meant to add 90-day reports. Until it's reliable, stick to the website or the office.