Assuming two identical twins want to swap their passports (e.g. to travel using the other guy's visa or to make visa runs easier) - would there be anything to stop them?

Some visas do record the applicant's fingerprints but would you really be banned from entering if just the fingerprints mismatch?


Does anything stop identical twins from traveling on each other's passports?

Technically, yes. It is illegal, that's the one thing that will stop most people.

In practical terms, can identical siblings use each other's credentials in many scenarios, yes, of course, especially if the picture is at least a year old.

The inclusion of multiple authentication factors though, such as fingerprints, make it much more difficult, especially when the intent it to verify identification.

However, keep in mind that verifying fingerprints in questionable situations is not a quick process. The software is very good at matching but an officer may still needed to verify the match. I would not be shocked (meaning I am admittedly speculating) to find out this step was skipped if the initial entry interview raised no suspicions.

  • When the machines works, it only takes a few seconds the verify the fingerprints. They have the machines on each immigration counter so it's not like they'll have to take you somewhere else for the procedure. If they have your fingerprints, there's a 99% chance they will ask you to verify. – greatone Mar 24 '17 at 18:22
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    They have them on each counter in the USA, UK and many other airports around the world. I'm not sure about other airports in the EU (they do collect fingerprints for visas)--but I am aware that the Schengen countries are trying to upgrade their biometrics systems for immigration services. – greatone Mar 24 '17 at 18:32
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    @tgb87 Those devices collect fingerprints. There is a huge difference between collecting prints and comparing/verifying. – Johns-305 Mar 24 '17 at 18:34
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    @Johns-305 they certainly verify and match them with the fingerprints they have previously collected (that's what shows up on their computer screens). I have been told that many times that my fingerprint isn't matching and that I must try again (or with another finger). – greatone Mar 24 '17 at 18:35
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    @Johns-305 That's not true. The verification is done by the computer and it's not really that complicated. Even our smartphones do this. Some countries even share fingerprints data with other countries without sharing any other details until there is a match. Then they share more. Do you think a human would go through millions of fingerprints to see if one matches? That's utterly ridiculous. – greatone Mar 24 '17 at 18:45

There is a good chance of being deported/removed if your fingerprints don't match. You will certainly be scrutinized more until they can confirm (based on a balance of probabilities) you are who you say you are.

Answer is based on experience. A family member's fingerprints couldn't be confirmed on one trip to the UK. They gave her a paper telling her they were deciding whether to let her enter or not.

I think the UK needs to upgrade their fingerprint machines. On many occasions it takes several tries until the fingerprints match.

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    "they were deciding whether to let her enter or not." - did they let her in in the end? – JonathanReez Mar 24 '17 at 12:18
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    Yes, they did... Immigration officers have a knack of knowing whether a person is genuine or not in a short conversation. That's what they're paid for. – greatone Mar 24 '17 at 12:25
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    Fingerprints typically don't scan well for older people. People who operate the fingerprinting systems know this. – kabZX Mar 24 '17 at 18:48

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