I already applied to get my US passport but I don't think it will be ready on time, I'm also a Mexican citizen, so, if I'm planning to fly from San Diego to Mexico City, can I do it with a Mexican passport? I also have a current green card that would probably work for the way back. I need to know as soon as possible, otherwise, I'll need to cancel my flight.

  • 5
    How do you have a "current green card" if you're a US citizen? Normally you have to return the card when you get naturalized. Regardless, the green card is no longer valid after you naturalize, because the card says that you are a permanent resident alien, which is no longer true.
    – phoog
    Commented Feb 16, 2021 at 9:16
  • Flying to Mexico City on a Mexico passport should be fine. It's returning when you are supposed to have a US passport
    – Midavalo
    Commented Feb 16, 2021 at 17:52
  • @phoog that sounds like an answer
    – mlc
    Commented Feb 16, 2021 at 19:02
  • @mlc unfortunately it is only half an answer, and probably the less useful half of the answer. I was hoping that a response to the question I asked might help point the way to the other half of the answer. I will try to remember to add an answer a little later when I have some more time.
    – phoog
    Commented Feb 17, 2021 at 1:50
  • This question is relevant, although I'm not sure the answer is conclusive (people seem clear that in practice you can leave on your non-US passport but some suggest it may technically be illegal; on return there are more checks): travel.stackexchange.com/questions/51933/…
    – Stuart F
    Commented Feb 17, 2021 at 12:02

2 Answers 2


Forget about flying back without a US passport; the airline will transmit your data to US authorities, who WON'T authorise the airline to let you board. Fly to Tijuana instead and cross the land border (e.g. via the CBX corridor at Tijuana airport), where you can explain your situation.

  1. Whatever you do, DO NOT ATTEMPT TO ENTER ON A GREEN CARD if you are a U.S. citizen. When you become naturalized, your green card is invalidated (you are supposed to surrender it as soon as you find it), so doing so can count as entry using an illegal document, and can lead to prosecution.

  2. To enter the U.S. from Mexico, you will need proof of P.R. status (or citizenship, in your case). If you can show them your U.S. passport on your way back, then you’ll be allowed back in. If you can arrange for this to work (e.g. have someone mail you the U.S. passport), then you should be able to get back in.

  3. It is technically illegal to leave the U.S. on a passport different from the U.S. passport. Mexico will let you in if you have their passport, but there might be problems on the way back. Again, I am not aware of any penalty for doing so; however, you might have some explaining to do.

  • Regarding the third point, there's nothing wrong with a US citizen leaving the US "on" a foreign passport as long as the US passport is in the traveler's possession. The law only says that one must "bear" a valid US passport, not that one must use it to check in for the flight. And many times there will be a need to check in for the flight with the other passport because of immigration procedures at the port of arrival. Also, as you suspect, there is no penalty for violating the law, as the former penalty was repealed in the 1970s.
    – phoog
    Commented Mar 23, 2021 at 7:06

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