Do I need to show proof of onward travel with a METV for entry into Thailand?

When entering Thailand on a METV (Multiple Entry Tourist Visa), proof of onward travel may be requested by the immigration officer, but it is not always strictly enforced. While it's advisable to have documentation like a return flight ticket, especially if you're on a back-to-back visa or visa-exempt entry, many travelers report that it is not commonly demanded. Airlines might also ask for a return ticket at check-in if you do not hold a visa, but having a METV generally alleviates this concern.