Hi, my wife and I will travel to Vietnam for some days in the end of July. My wife has a Thai passport that expires soon and will get a new passport when we get to Bangkok. Can I book the tickets to Vietnam using her old passport number, will she then have issues when showing her new passport? I want to book before we leave since our holliday is 5 weeks and I will need to get out of Thailand before my 30 day is up. Maybe I can change the passport number on bamboo airways's website before our flight (didn't get a respons on the email I sent to their Vietnam Office)?
TLDR : Answer Summary
The main concern is whether you can book tickets to Vietnam using your wife's soon-to-expire Thai passport number and if this will cause issues during check-in with her new passport. The consensus is that what you enter at the booking stage is not crucial; however, it is essential that she obtains her new passport before traveling. Most airlines do not require passport information until check-in, and it's advisable to ensure her new passport is ready, as many Southeast Asian countries have a requirement for at least 6 months of validity on the passport.