Is it acceptable to make a flight reservation to Vietnam after spending 20 days in Thailand if I haven't received my visa yet?

Nothing to do with visa BUT a problem arose boarding EVA from Seattle to Bangkok. They wanted to see the physical credit card I used to purchase the ticket. I didn’t have it because that card had been lost or fraudulently used after I bought the ticket. The card was replaced. EVA was absolutely not going to let me board unless I could prove to them that my card had been replaced by my issuing bank. But a supervisor, after reviewing all my hotels & onward flights were booked with that card, did let me board. It is in the small print of their ticket contract that they may ask to see the original form of payment.

I use bus tickets, 12go.asia, Hat Yai to Penang.

@Adam ********

. . . in case you intend to throw the ticket away after arriving to Thailand, I suggest a cheaper option. Buy an Air Aisa one-way ticket from Hat Yai to Kuala Lumpur. It is something like 30.- USD. Note to self - this will be a REAL ticket. So called "fake onwardtickets" are only reservations, and CAN get refused by the airline

I just went through this. Same situation. EVA did not ask to see Visa or onward flight within 30 days. However the desk agent did ask.

Buy an onward ticket (look it up on internet) to get you on the plane then in Thailand you can extend your voa.

Yes, just buy the cheapest flight out

Yes totally

Have you checked they haven't asked for further information for your visa application?

Having a return flight is enough. It doesn't matter when, because you can extend visa exemption for a further 30 days in Thailand