I have both valid US and UK passports as a dual citizen. I plan on traveling from the US where I live to the UK on vacation. My question is when I book my flight ticket with British airways which passport do I need to input when booking? I am concerned that if I input my UK passport that I may run into issues on the return journey. Does anyone have any recent experience of this following the recent regulation changes back in February 2026? I will take both passports with me.

You can use either passport on the booking, as it doesn't have any bearing on the one you actually show to immigration at either end.

It doesn’t particularly matter since you’ll need to show other one at check-in for the other flight. If I was living in the US however then I’d add your US passport details to the booking and show your British passport at check-in on the outward leg.

Just so I understand:

- Leaving the US you show your US passport
- Arriving in the UK you show your British passport
- Leaving the UK you show your British passport
- Arriving in the US you show your US passport

Is this the correct sequence?

There are no formal passport exit controls in the US or UK so you should check-in with your British passport when leaving the US and use it in the ePassport gates on arrival in the UK.

On the way back, check-in with your US passport and present it to CBP on arrival in the US.

I'm interested in what you did in practise for all entry and exit as I am in the same situation pertaining to the UK ETA.

If you have a valid ETA linked to your US passport then you can travel on that for your entire trip.