Do I need a return ticket when applying for a Non-O visa in Thailand?

When applying for a Non-O visa or upon entry into Thailand with this visa type, a return ticket is generally not required. Several commenters confirm that they were not asked for a return flight when entering Thailand on a long-term visa like the Non-O. It's advisable to confirm current requirements directly with relevant authorities or the airline, but indications suggest that having a return ticket isn't necessary.