When do I need a re-entry permit?

If you leave Thailand after receiving an extension of stay but without getting a re‑entry permit first, the extension is effectively cancelled and you will not be able to rely on it to return. You must obtain a re‑entry permit (single or multiple entry) from Thai Immigration before you depart if you want to keep the current extension valid for re‑entry. Without it you either need a new valid visa/entry permission to come back, or you must re‑apply for an extension after returning (which may require leaving and re‑entering on an appropriate visa). For practical next steps: • Before any departure, visit an Immigration Office to get a single or multiple re‑entry permit. • If already left without one, check your current visa type and arrange a new visa at a Thai consulate or entry at the border (note: border crossings/visa runs are currently not recommended). Official guidance: Thailand Immigration / thailand.go.th re‑entry and extension pages.