My partner (Australian) and I (American) are visiting Canada and the US in October. Our last flight back home involves either a 4.5-hour layover in LAX or a 1.5-hour layover in SFO. Both options are single ticket through either Delta (LAX) or United (SFO), United being the flight with a 1.5 hr layover.

I am more than sure that the 4.5-hour layover will be overkill, as I will go through immigration quickly and he should be a bit quicker, as he will be able to use those kiosks for non-residents who have visited the US in the last 5 years (we will have just spent 2 weeks there prior). Still, 1.5 hours ins't a lot of time. My questions are:

  1. Are we required to go through immigration/customs for an international to international flight?
  2. Is 1.5 hours enough time?
  • The same question as usual: booked as a single ticket or as two separate tickets? Also note that I believe you will go through immigration checks in Vancouver, not SFO (preclearance), others will confirm.
    – jcaron
    Aug 4, 2018 at 8:35
  • Which airlines are involved? Whether or not you'll need to change terminals and go through security again depends on the airline choices. Also, one ticket or two? You'll go through US immigration and customs in Vancouver, so that's not an issue. Aug 4, 2018 at 8:35
  • Single ticket either through Delta or United. Will add info to post.
    – grahamfw
    Aug 4, 2018 at 10:19
  • 2
    @grahamwf There are no Delta flights direct from SFO to Sydney, is this a codeshare or are you going via LAX? Aug 4, 2018 at 13:28
  • Oh sorry, I got mixed up, the Delta one is through LAX.
    – grahamfw
    Aug 5, 2018 at 1:00

4 Answers 4


If it's two United flights, then all you need to do is walk to the next gate, nothing else involved. The Sydney flight will leave from the international terminal, which is connected to United's Terminal 3. That could take more than 5 minutes (a ~3,500 ft walk, with some moving sidewalks, is the worst case scenario if they're as far apart as possible), but you won't have to go through immigration/customs or security or handle your checked bags or anything else at SFO.

You will have to go through US immigration/customs in Vancouver (all passengers do, even for international-to-international connections in the US), so be sure to arrive at the airport extra early.

Delta does not fly from SFO to Sydney, but if you're flying Delta into SFO, you'd need to change terminals to reach any flight to Sydney, which will take more time and mean you need to go through security again.

1.5 hours should be sufficient if your flight is not significantly delayed, but it, as jpatokal points out, only leaves so much margin for delays before connecting to a flight that leaves once every 24 hours. If your flight from Vancouver is sufficiently late, you'll likely be waiting until the next day for another flight. Whether or not that risk is acceptable to you is up to you, based on your need to be in Sydney that day.

  • Good to know it's not a huge trip to get to the next flight. I did get mixed up with the delta flight as it does not go through SFO, it goes through LAX and costs $150 more per person. Between dealing with LAX and the additional cost, I would much prefer the shorter flight, but that cost will get eaten up if I get stuck there overnight. Thank you for your help!
    – grahamfw
    Aug 5, 2018 at 1:05
  • If you get stuck in SFO overnight, with the two flights booked on a single ticket, it will be the airline’s responsibility to pay for your hotel and meals and possibly transportation. Of course, they’ll probably have you stay at a hotel close to the airport rather than downtown. Note that in case of a delay of the incoming flight, another possibility is for you to make the connection but not your bags, so plan for that.
    – jcaron
    Aug 5, 2018 at 12:33
  • 1
    @jcaron United will likely claim that the delay is outside of their control due to weather unless there's clearly a mechanical issue or something or you're a top-tier frequent flyer with them. They'll put you on the next flight, but not necessarily pay for your hotel. Aug 5, 2018 at 19:47
  1. Usually you would both have to go through immigration, since the US does not recognize the concept of sterile transit. This includes collecting and rechecking your bags. However, @ZachLipton correctly points out that YVR is a preclearance airport, meaning you will complete this in Canada before your flight to SFO.

  2. On paper the minimum connecting time for international to domestic/intl is 80 minutes, so if you have already checked into your connecting flight and have no bags, it's technically feasible (especially with the preclearance) but uncomfortably tight. However, since you're connecting to a flight to Sydney, if you miss it you'll be stuck for a minimum of 24 hours waiting for the next one, since all flights to Australia leave around the same time. So I'd strongly encourage you to play it safe and take the 4.5 hr connection.

  • 2
    I agree with your ultimate conclusion to play it safe given the consequences of misconnecting, but Vancouver is a Preclearance airport, so no immigration is required at SFO. Aug 4, 2018 at 8:39
  • @ZachLipton Excellent catch! Correcting answer. Aug 4, 2018 at 9:50
  • 1
    Thank you @jpatokal and zach lipton. I figured as much. I was hoping that the bonus of same terminal (assuming since it's 2 international United flights) and no immigration would make it a 5 minute walk or something. I've also had the luxury of flying domestic in Australia for so long that I have forgotten how difficult the process can be.
    – grahamfw
    Aug 4, 2018 at 10:28
  • Does United provide a free hotel to passengers who have missed their flight for reasons outside their control? If so, it could actually be a great opportunity to explore SF :)
    – JonathanReez
    Aug 5, 2018 at 7:57
  • @JonathanReez Officially, only if the delay is within their control, meaning they'd most likely blame the weather and say that's not in their control. If you're a frequent flyer with them (especially 1K), they very well may do more for you. Also, the hotel could be covered by travel insurance or credit card insurance. Aug 5, 2018 at 8:59

Almost all flights from Vancouver to the US go through preclearance, which means you will arrive in San Francisco as a domestic flight, without any special procedures. And departing international flights in the US are procedurally identical to departing domestic flights, as the US has no exit checks; you simply walk onto the flight from inside the terminal just like a domestic flight (sometimes gates for departing international and domestic flights are next to each other with no difference in appearance). So basically this is no different from a domestic-to-domestic connection.

Depending on which terminals your flights are arriving and departing from (you have not provided enough information to tell), you may have to leave the secured area and re-enter security. In that case, you should leave extra time for the wait in the security line. 1.5 hours is probably enough if there is no delay in the first flight, but it is cutting it close if there is any delay.


One more problem: SFO has a fog problem--their main runways are too close together for instrument flying rules. Visibility drops, the airport capacity gets cut in half. Generally 90 minutes is fine for a connection at SFO, but twice now (out of maybe 20 connections) I have arrived more than 90 minutes late due to fog. (The first time we just barely caught our flight, the second time I knew better and was on an earlier flight, the recommended flight landed after we were already sitting on the second plane.)

Thus I will not book a connection that short at SFO, period.

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