When do I need to report to immigration or do a border run in Thailand?

When entering Thailand with a DTV visa, you are not required to report to immigration if your stay is less than 90 days. If you remain in Thailand for 90 consecutive days, you must report to immigration at the office where your TM30 registration is filed. You can choose to leave before the 90-day mark without a report, and each departure resets your stay. After the initial report, the requirement for stamping every 180 days or additional 90-day reporting may depend on future stays.