Can a Belgian passport holder enter Thailand for 30 days without an onward flight ticket?

A Belgian passport holder can enter Thailand for 30 days under the visa exemption and extend their stay for an additional 30 days. Upon entry, proof of leaving Thailand before the end of the first 30 days is normally required, but this is primarily checked by the airline prior to boarding, rather than Thai immigration. Many travelers report that immigration does not consistently verify onward flight details, and having a refundable return ticket can serve as proof for the airline. Despite this, there are scenarios where immigration could deny entry based on other factors.