Regulation (EC) No 883/2004 applies:
- since May 1, 2010, to nationals of EU states in relation to individual EU states,
- since January 1, 2011, to third-country nationals with lawful residence in an EU state (except in relation to Denmark or the United Kingdom) in relation to individual EU states,
- since April 1, 2012, to citizens of Switzerland in relation to EU states (Croatia since January 1, 2017) and vice versa,
- since June 1, 2012, to citizens of EEA countries in relation to EU states and vice versa,
- since January 1, 2016, to citizens of EEA countries in relation to Switzerland and vice versa, and
- since January 1, 2021, based on the withdrawal agreement, in relation to the United Kingdom.