The Customs Union is the first Regional Integration milestone and critical foundation of the East African Community (EAC), which has been in force since 2005, as defined in Article 75 of the Treaty for the Establishment of the East African Community.

It means that the EAC Partner States have agreed to establish free trade (or zero duty imposed) on goods and services amongst themselves and agreed on a common external tariff (CET), whereby imports from countries outside the EAC zone are subjected to the same tariff when sold to any EAC Partner State.

Goods moving freely within the EAC must comply with the EAC Rules of Origin and with certain provisions of the Protocol for the Establishment of the East African Community Customs Union.