However, identity documentation is still useful, as companies may require proof of identity for certain services, such as trains, airports, age check for alcohol purchase, or for services aimed at residents, like banking, picking up postal packages or dealing with authorities[citation needed].

The Faroe Islands are part of the Nordic Passport Union[1] but not the Schengen Area, while Greenland and Svalbard are outside both.

[10] From 25 March 2001, the Schengen acquis applied to the area of the Nordic Passport Union with the exception of the Faroe Islands.

Border checkpoints have been removed within the Schengen Area, in addition to those that had been abolished previously within the Nordic Passport Union.

Still laws give police and guards the right to demand an identity document at airports[12] The protocol concerning the abolition of the requirement for passports to permit travel between Sweden, Denmark, Finland and Norway[13] was signed on 14 July 1952, in Stockholm.

On 26 July 2014 the Norwegian police for the first time suspended this agreement due to a perceived terrorist threat.

The agreement between Denmark, Finland, Norway and Sweden to remove passport control at the internal Nordic borders,[17] was signed on 12 July 1957 in Copenhagen and came into force on 1 May 1958.

Aliens with residence permits are allowed to stay up to three months in other Nordic countries, except for seeking employment or conducting business.

In November 2015, Sweden and Norway introduced temporary border controls, and requirements for all international airlines and ferries to check identity documents, due to the European migrant crisis.

[18] These controls were heavily criticised for violating the rules laid out in title III of the Schengen acquis[19] prohibiting such carrier responsibility within the Schengen area,[20] and were subsequently abolished by the Swedish government on 4 May 2017 to avoid potential formal sanctions.

[21] At the border, a traveller will need to be able to present a passport (and appropriate Schengen visa if required), an EU/EEA national ID card,[22] or a Nordic driver's licence.