The European Economic Community’s customs union entered into force in 1968.
The customs union was a foundational step in European economic integration. Its members removed customs duties on trade between participating countries and applied a common external tariff to goods entering from outside the community. This meant that internal trade could move without ordinary customs tariffs while imports from nonmembers were treated under shared tariff rules.
The Treaty of Rome, signed in 1957, set the objective of creating the customs union, but the system became operational on 1 July 1968. The six founding members were Belgium, France, Italy, Luxembourg, the Netherlands, and West Germany.
The customs union is not the same as the European Union single market, which began in 1993 and also addressed barriers such as regulations and movement of services. A customs union focuses especially on external tariffs and customs treatment.