I am arriving on American in terminal 3 and leaving on BA to Berlin from terminal 5. Do I have to go through passport control in LHR or TXL? How long does it take to get from term. 3 to term. 5? Connection time only 1 hr 40 min. AA says enough time, but I'm not so sure.
I think it will be a little tight.
I don't know whether you have to go through immigration or not - depends I think on whether you have your bags checked through. If you don't have them checked through, you probably have to get your bags and recheck them.
You DO have to go through security again in LHR from one terminal to another, or even from one place to another within one terminal. This means liquid restrictions and taking off your shoes and belt, and they scan you and your luggage again. But that isn't immigration, it is just passenger security.
When transferring in the UK your citizenship is irrelevant unless it is a country which requires a DATV (direct airside transit visa) or Visitor in Transit visa.
Assuming you are travelling on a through ticket (i.e. already have your boarding pass for the BA flight) your bags will be checked through to Berlinand you will not need to formally enter the United Kingdom You will be able to transfer T3>T5 airside using dedicated transfer passenger buses.
You won't go through UK border control but your boarding pass and ID will be checked and both you & your cabin bags will go through full security scanning.
You can check the exact process for your particular flight connection on the official airport website:
For very obvious reasons, airlines do *not* sell flights with impossible connections. 1h 40 minutes will be plenty of time as long as you have no inbound delays....but don't dawdle. Wait until you are at T5 before you have a coffee or go to the loo! :-)
You will go through formal border control on arrival in Berlin. The United Kingdom is not part of the Schengen Area so, even if you did formally enter it during your transfer, you would still go through border control on arrival in Germany.
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