Is it necessary to have a return ticket while entering Thailand on a tourist visa?

It is essential to show proof of a departure ticket when applying for a tourist visa for Thailand, particularly if using the e-visa system or if applying at an embassy. While a return flight is not mandatory, a ticket to exit Thailand within the allotted days (60 or 90 depending on the visa type) is needed. For those entering under a 30-day visa-exempt entry, airlines may require an outbound flight ticket, so checking with the airline beforehand is advisable.