How long can I stay in Thailand if I leave three weeks before my ED Visa expires and return one week later?

If you leave Thailand three weeks before your ED Visa expires and return one week later, you will need to consider how the immigration rules apply upon your re-entry. Generally, upon re-entering Thailand, you may receive a 30 or 90-day visa exemption, depending on your nationality. However, your stay may not extend to the expiration date of your ED Visa, and you will need to confirm whether you can stay based on your visa exemption conditions.