When EU citizens work abroad in other EU countries, Iceland, Liechtenstein, Norway, or Switzerland, mobility documents allow social security benefits to be claimed. A great deal of information is exchanged directly by the social insurance carriers; however, those insured often need a separate mobility document for submission to employers or government agencies. These documents – for example, S1-S3 (healthcare), DA (occupational accident), U1-U3 (unemployment), A1 (posting) or P1 (pension) – are issued by the insurance carriers.

Source: Europäische Kommission, edited