Departure time of the next flight is just 1 hour and 20 minutes after the arrival time of the first flight. Can I make it? The first flight is a short trip from Taipei to Bangkok so perhaps it’s unlikely that this will be delayed? Luckily I don’t have any check-in bag.
Also it says it’s “self-transfer” which means “You may need to check in separately for each connecting flight. Make sure you have enough time. You may need to: Pass through security and passport control.”
Every time I have a connecting flight in Bangkok it’s been around 40 minutes. I’ve never had a bad experience. I suppose there could be a delay on your flight into Bangkok.
Are you dealing with two different carriers?
There are two airports in Bangkok that has international traffic.
Are they the same airport?
If it’s on the same ticket you’ll probably be immune to the most likely problem (delayed first leg). The fact that you have no check-in bag makes things a whole lot easier.
IMO you need to ensure that you don’t have to go out through immigration and come back in again. Go to the transfer desk and get them to talk you through it. I wouldn’t like to attempt it myself, but 1:20 should be fine as long as you get a move on and don’t mess around.
Self-transfer usually means you’ve been booked on two different tickets, so you’d have no backup if your first flight is delayed. Whereas, if it’s one ticket, the airline is obliged to put you on their next flight. Big risk.
Yes same airport Suvarnabhumi. Thankfully!
Thai Vietjet and Thai Airways. They were being sold as a bundle, but they were warning that it’s “self-transfer”. Not sure if it means what it means to be “same ticket” or not.
It means that if for any reason you arrive late in Bangkok, your connecting carrier (I presume that would be Thai Airways) will simply consider you to be a no-show. This means you’ve lost the ticket, no refund, no help when you eventually arrive with a sad look on your face, plus a possible additional no-show fee. If you make it, great; if you don’t, that will be the result.
Guy
If you come in at the same time as other flights. the line at immigration can be long. Not sure if they’ll take pity on you and let you go first or not.
What website did you purchase from?
Where are you flying to after that? I’m guessing it’s somewhere else in Thailand if you’re flying with Thai Airways? Also, like @projectmaximus said, who did you book with?
If your next flight is within Thailand and you need to go through immigration at BKK, 1 hour 20 min would seem a bit tight to me. I don’t think it’s impossible, but any delay to your flight from Taipei and/or a line at immigration could make it tricky. I remember the domestic terminal at BKK being quite okay though, and at least you’re in the right country if you miss the flight.
If your next flight is outside of Thailand, I wouldn’t want to risk it.
If your Thai Airways flight is domestic then maybe you can change to a later time and give yourself some breathing room
Thai Airways will fly from Thailand to Europe.
Too risky
If you can change the air Asia flight, do it for the day before and get an airport hotel or stay somewhere near the airport
Maybe it will be ok if you only have carry on and don’t need to go through immigration
I’m with @OrangeOrganics . This kind of connection carries too many risks. Either get an LCC flight the day before (or a few days before and enjoy Bangkok 
) OR just book one ticket straight through to Europe on Thai Airways or some other airline of your choice.
Guy
Just thinking about it, the full service carrier is going to be more accommodating than the low cost one.
Maybe contact Thai Airways and tell them that you are worried about missing your connection and what would be the penalties if you did and can they put you on the next flight/flight next day
Alternatively, maybe for free or for a charge, they will let you move you bkk to Europe leg to the next day. Then just get an inexpensive airport hotel or hotel in Bangkok and come back the next day. Will need to spend a bit more and will arrive a day later but you will save a lot of stress
Yeah, I would find that too risky too. Would definitely check with Thai Airways/Kayak to see what happens if you miss the second flight.