National Identification Number for ESTA

When applying for an ESTA to travel to the United States, you will be asked to provide your National Identification Number. Learn what kind of number this is and what to do if you don't have a National Identification Number.


Die offizielle Einreisegenehmigung für die USA!

What is the National Identification Number?

Many nations issue their citizens with individual numbers used for certain government functions (e.g., taxes and social security benefits).
These identification numbers are also queried outside your country's borders — for example, if you apply for ESTA to enter the United States.

However, each country uses a different term, which is why phrases such as “Personal Identification Number,” “National Insurance Number,” or “Personal Identification Code” are circulating, too.

Which number goes in the ESTA application?

Not every country has a National Identification Number (NIN). Instead, alternative numbers such as the tax identification number, the social security number, or the ID card number are used in many places.

As a rule, if your country does not have a NIN, you do not have to enter one in the official ESTA application form (the corresponding field is grayed out). However, there is confusion because, for some countries such as Germany, the Netherlands, or Belgium, there’s an exception to this rule.

In these cases, not having a National Identification Number but being asked for one during the ESTA application means that you must provide the serial number of your national ID card.


While some ESTA websites suggest entering "UNKNOWN" in the field for the National Identification Number if one is unavailable, the US Customs and Border Protection (CBP) agency advises using the serial number of your ID card as an alternative.

Entering the USA on an ESTA

If you have provided both your passport number and your national ID card number (as a substitute for the National Identification Number) during your ESTA application, you must carry both documents when entering the United States. Also, stay up to date with the current entry requirements for the USA.