Transit through NRT
 

I'm traveling to Vietnam next month on JAL DFW-NRT-HAN in J.

My first leg arrives at NRT at 2:25pm and departs for HAN at 6:00pm same day
Return leg arrives at NRT at 6:30am and departs for DFW at 10:55am same day

My understanding is that transit is allowed without covid testing (USA is blue category, Vietnam is yellow category, and I'm triple vaxxed), so I should be fine for those flights as I won't need to enter Japan.

However, my question is worst case scenario. What if I make it to NRT and then when I'm there, one of the flights out of NRT is cancelled and I am not able to be rebooked that same day? Does anyone know what happens in this situation since NRT isn't open overnight and I wouldn't be able to enter Japan? Can I stay in terminal 2 airside? How often are flights cancelled and people end up in this situation? I find it strange that Narita isn't a 24 hour airport.

Thanks!

Probably no way to answer this 100%, as so many scenarios can play out, but most likely you will just overnight in NRT. While it's technically not an overnight airport (you can't book a flight connecting overnight), there are times when people have to overnight. It won't be fun, you won't get lounge access, but there will be a section of the terminal blocked off for such situations. The biggest issue is the expired covid test to come back to the US...can you get another one at NRT or would you not be able to and they send you back to Vietnam (i'd personally fight tooth and nail to prevent this). Kind of up to the airline...and flying JL might have it's benefits in this case. Here's a worst case scenario that had possible chaos and definitely a lot of confusion:

https://www.flyertalk.com/forum/air-...onnection.html

Thanks. I'm planning to use a proof of recovery letter from recent covid infection instead of a negative test so I guess in the unlikely event of problems at least I won't have to scramble for a new test. Probably will take some home antigen tests with me just in case.

Not focussed on this specific situation but the general consensus has been that recovery letters do create a bit more scrutiny as every one is different and some individuals who need to check them query them more. If you are able to present negative tests for travel then you may reduce risk of delays or queries. Good luck with your trip.