Are 3 hours enough time to change planes at London-Heathrow? Will I have to go through security again?

My first leg is Zurich to London-Heathrow (with Swiss) and my second leg is London-Heathrow to Halifax, Nova Scotia (with Air Canada).

  • 6
    Were the two flights booked as one ticket (one PNR) or two separate bookings?
    – Traveller
    Apr 22, 2022 at 6:28
  • 2
    Are your flights arriving to and departing from the same terminal at LHR? Which one?
    – brhans
    Apr 22, 2022 at 8:24
  • It is one ticket (booking) through Air Canada. Using the link given in Hilmar's answer, I will arrive and depart on Terminal 2 and require 60 minutes.
    – Thomas
    Apr 22, 2022 at 12:48

2 Answers 2


This depends a lot on your specific details, but the likelihood of making it is pretty good.

Check your details here on Heathrow's Connecting Flights web page.

If you are on one ticket, this is more than enough unless something really unusual happens. Even if it goes sideways, the airline will take care of you.

If you are on two separate tickets, things are more complicated:

  • If you don't check luggage and can check in online for your second flight you can just follow the signs to "connecting flights" and go to your gate. You will have to go through security and boarding pass check, but probably not through immigration and customs. Three hours should be fine for that.

  • If you have checked luggage, things are considerably more difficult. You need to wait for your bags to come out and then clear customs and immigration. Then head to the check in counter of your second airline and drop of your bag there, clear security and go to your gate. 3 hours can be tight for this.

I came in this morning to Heathrow from the US transferring to the EU (single ticket, no luggage, no immigration, same Terminal), and I made it in less than 30 minutes. Biggest hold up was connection security which wasn't full but extremely slow with only one line open. On the other hand there was a guy in the terminal that holding passengers downstairs since apparently immigration was so overcrowded that they couldn't let any more people into the immigration hall. No idea what the actual wait time currently is (I'm writing this while still being at Heathrow) but my guess is it's substantially more than an hour.

The biggest problem with two separate tickets is that you are fully responsible for a missed connection. If you are late, you may have to buy a new ticket on the spot which can be VERY expensive.

  • @Hilmar, I used your link. That link is very helpful! Yes, it is one ticket (one booking). According to the form in the link, I need about 60 minutes to transfer.
    – Thomas
    Apr 22, 2022 at 12:49
  • 3
    "I just did it this morning, actually, I'm still at the airport" seems like it's pretty accurate info!
    – FreeMan
    Apr 22, 2022 at 17:18

If it is a through ticket you have plenty of time. Both carriers are Star Alliance members and they work together.

  • Yes unless you have to clear Immigration in Heathrow.
    – Don Hogan
    Apr 24, 2022 at 4:13
  • @DonHogan no need for that, LHR has sterile connecting solved.
    – user4188
    Apr 25, 2022 at 2:09

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