I went to the passport office of my (highly developed Western) country and they said they wouldn't know if a foreign country I had previously overstayed in had banned me or not just by scanning my passport.

Isn't that the point of passports? To contain data and violations on each traveler, and that data is shared between all countries who "access" or scan the passport to make a decision on whether to admit them or not? Do countries not share information about foreign travelers with all other nation states via their passports?

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    In addition to the answers's you've been given, passport scanning does not reveal any more information than you can see on the page. It's just a way for computers to access the data more easily.
    – CMaster
    Mar 1, 2023 at 17:33
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    @user610620 ICAO Doc. 9303 Part 1 volume 2, the same standards as for passports. Note that it does indeed note that there is an optional space for e-visa data and such, but it is not part of the actual standard yet Mar 1, 2023 at 19:18
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    If it were stored in the passport, one could just conveniently lose the passport and be done with the ban. Of course it’s not in the passport. Also remember millions of people have two or more passports.
    – jcaron
    Mar 1, 2023 at 20:06
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    @CMaster that is incorrect. Some passports, for example, hold digital fingerprints in the chip without making those fingerprints available for visual inspection.
    – phoog
    Mar 1, 2023 at 21:20
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    Note that the passport office of your country is primarily concerned with issuing passports and has little to do with whether or not you're in good standing in any other country (excepting odd situations such as your passport being revoked because you're a fugitive or something). While there are circumstances in which countries may share certain information, there is no global registry of "violations" known to your passport office. The passport office in, say, Canada has nothing to do with and likely no information about whether a Canadian citizen once overstayed their visa in, say, Thailand. Mar 2, 2023 at 2:08

3 Answers 3


Isn't that the point of passports?

Historically, the point of passports was primarily to prevent people from leaving without authorisation. This mechanism can still be used, e.g. when a court forces you to surrender your passport.

In our age of paranoia about immigration, passports are also used the other way around: As a kind of guarantee that you can be expelled if need be. The country issuing the passport thus more-or-less accepts a duty to take you back.

To contain data and violations on each traveler, and that data is shared between all countries who "access" or scan the passport to make a decision on whether to admit them or not?

The passport, even a recent biometric passport, doesn't contain any data that would be updated after having been issued. The chip mostly contains the data that's visible on the ID page, together with a digital picture and potentially fingerprints. These data are encrypted with a key based on your biographic data. Currently, the only way information is added and shared widely is just through the good old-fashioned stamps you can check yourself.

Scanning the machine-readable area (the strip at the bottom of the ID page) serves two purposes:

  • Reading the contents of the chip to detect any alteration of the document and compare the contents with the face and fingerprints of the person trying to cross the border
  • Automatically pulling some data (like your name and date of birth) to run searches or even save it in some national systems or check if your passport is on some list of invalid document without having to type in the details manually

Do countries not share information about foreign travelers with all other nation states via their passports?

They mostly don't share information (by any means), with much more limited exceptions than most people seem to assume. It's easy to realize that the US, Iran, Russia, and Venezuela (to name a few) are not going to let each other access up-to-date biometric data about their citizens so you shouldn't expect some sort of worldwide system for that. Even within the Schengen area, where the principle of a central register of entries and exits has been agreed upon and the legal framework has been finalized for years, implementation is a significant challenge.

Note that all this is clearly distinct from information exchange for intelligence purposes. Collaboration between countries on this doesn't mean the data is widely available to all law enforcement officers. That's not how intelligence data is handled.

  • Could the bottom strip of the passport, when scanned, be the mechanism by which a US border agent would find out that someone was banned from Spain, for example, given that the bottom strip pulls data used to run searches, and save new information, to national systems?
    – user610620
    Mar 3, 2023 at 0:25
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    @user610620 That's not what “national” means, that would imply that Spain grants full access to its national systems to the US.
    – Relaxed
    Mar 3, 2023 at 7:15
  • So the bottom strip of the passport does not contain information that is shared between countries? The passport holder's home country's passport office will tell the passport holder that the other strips above the bottom strip are the only ones their home country would access, and that the bottom strip is the one used by foreign countries, like what you say. So wouldn't you think, if all foreign countries are using the bottom strip of the passport, you'd think that there's alot of data inside that bottom strip? Therefore, shared by everyone who's used that bottom strip?
    – user610620
    Mar 4, 2023 at 15:36
  • @user610620 You can read the data that's on the bottom strip (“machine-readable zone”) yourself, it's just a bunch of numbers and letters. It doesn't get updated or contain much data, mostly your name, nationalty, date of birth, document number and expiration data. These data can then be used to decipher the data that's on the chip, which can also be read by anyone (other countries but even yourself with a smartphone) without any data exchange. It doesn't include any travel history or any updated data compared to what you submitted when applying for the passport.
    – Relaxed
    Mar 5, 2023 at 11:03
  • I also have the feeling this has already been explained to you in details. How it works is pretty technical but the bottom line is that no data is being exchanged between countries to make it work and your passport doesn't contain anything beside the information you can read yourself and some biometrics (facial picture, fingerprints). Do you find that difficult to accept?
    – Relaxed
    Mar 5, 2023 at 11:04

No, that is absolutely not the purpose of passports.

The purpose of a passport is to demonstrate that you have the identity and citizenship that you are asserting, and to use that to decide whether to admit you into a country or not. It is also a secure place to store visas that have been issued to you, and proof of when you arrived at (and in some cases, but not all, left) a country. Some countries may use that record in addition to your identity and citizenship to make decisions (not letting you in if you have a stamp from a specific other country) but this is the exception, not the rule. Others may use it to confirm that you are someone who enters countries and then leaves again as planned, increasing their confidence in letting you in. But this is not the purpose of the passport, merely a side effect some countries use in some cases.

Passports do not contain violations, except occasionally when a visa or entrance stamp will be "cancelled" such as by an officer drawing an X over them. Some governments keep lists of violations, and some share those lists with other countries, but it's not universal. When they do share, the mechanism they share with is not your passport, but another form of communication.

The scanning is a quicker way for the officer to enter the information needed to look you up in some system that the officer has access to. This will not be a giant international system shared by all the countries of the world, but something specific to that country and whatever lists it may have of people who have been banned or who are going to get extra scrutiny on each entry. There was a time when the officer typed those things in by hand, but now they can generally swipe instead, or you can put your passport on a scanner and do the whole thing without interacting with a person.


Isn't that the point of passports? To contain data and violations on each traveler, and that data is shared between all countries who "access" or scan the passport to make a decision on whether to admit them or not?

The passport is just an identity document that has some stamps. A passport is not the right to enter a country. That would be called "citizenship" :)

It's also not really a data port. It's not like a team of technologists led by Elon Musk did a from-scratch reboot of passports using 2018 tech. The whole world has to agree to basic technology changes. It's been 2500 years of incremental improvements.

That said, each of the countries try to do their best with off-passport databases... and a few of them share data. EU obviously, but the Five Eyes and EU as well.

You apply for a visa

Thanks for the information, but there is still no resolution to the issue: How then does someone find out they are banned from a country before traveling, without attempting to cross that country's border?

You go ahead and apply for a visa to that country, in the normal fashion. That's it. They either grant you a visa or they do not.

"But I don't want to apply for a visa! My citizenship country has some sort of visa waiver with my destination country, and I'm able to do a visaless entry normally. I want to know if I broke that by violating their rules."

You already (should) know if you broke their rules

That's your answer. They usually publish their rules, so just compare "their rules" to "your behavior" and that should settle it.

"But I want to know if they FOUND OUT about it". Okay LOL. I hate to say the answer is usually "yeah, they know". But I gather you are not an immigration lawyer who specializes in that country, so you may not have ALL of your facts straight about whether what you did is the kind of thing they ban you for. There are 3 ways to find out.

  • Talk to an immigration lawyer who does specialize in that country.

  • Attempt another visa waiver entry and see what happens but make room on your credit card, as you may be about to pay full price for a same-day return airfare. Note that if a country does preclearance at a given airport, use that route! That way you avoid a miserable and wasted double flight, and may even be able to salvage a respectable holiday getaway out of it. (e.g. if in the EU going to USA, book through Shannon Ireland - make plans for both a USA holiday and a Shannon holiday.)

  • (the surest, safest method) apply for a visa, as discussed. That also gives you the best option to explain your case for why the previous transgression should be overlooked, since you have the opportunity for a written and organized statement with unlimited supporting docs, not the hostile chaos of an immigration desk at an airport.

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    If the country in question is a Schengen country, good luck getting them to entertain a visa application with a visa-exempt passport.
    – phoog
    Mar 2, 2023 at 22:05
  • @phoog: Well, you can try to apply for a visa category that's outside the basic visa exemption.
    – MSalters
    Mar 3, 2023 at 9:22
  • 'A passport is not the right to enter a country. That would be called "citizenship"' is not quite true. A visa is also a [limited] right to enter a country, and has historically been placed into the passport (though it seems they're increasingly purely electronic but tied to the passport).
    – Auspex
    Mar 3, 2023 at 15:08
  • @Auspex With a visa you're likely to get in, but you can still flub your entry interview or have an extenuating circumstance like COVID-19 happen or Trump's "ban 7 countries" thing happen, and still be turned away. You call that a [limited] right, but I don't think it's a right if it's [limited] - then, it's just a privilege. Mar 3, 2023 at 22:38
  • @phoog are you saying that if a visa-exempt national is refused entry to EU, then their only option is to keep trying to make visa-free entries and hope to clear it up at the immigration desk on landing? That would be a very broken system. Normally, "I was previously refused entry" makes applying for a visa reasonable - why is EU different? Mar 3, 2023 at 22:46

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