All Member States are part of the EU Customs Union and apply the same customs rules and procedures. This implies full legal compliance, proper implementing and enforcement capacities, as well as access to common computerised customs systems.

The policies in Chapter 3.29 Customs Union are the basis of the European Union and are a basic element in the functioning of the single market. The single market can only function properly if there is a common/identical application of common rules at the external borders. This means that all EU customs administrations should act/function as one. These common rules even go beyond the concept of a customs union (with its Common Customs Tariff) and extend to all aspects of trade policy, health and environmental controls, the common agricultural policy, and the protection of the EU economic interest through non-tariff instruments, measures related to foreign policy, etc. Today, customs face new challenges: to ensure smooth trade flow by applying the necessary controls on the one hand, but also to guarantee the protection of health and safety of the citizens of the Union. To ensure a balance between these requirements, customs procedures and control methods must be modernised while also strengthening cooperation between the various customs services. Customs IT systems are also a very important segment, so to improve the interoperability between the customs systems of Member States, the Council and the European Parliament have decided on a "paperless environment for customs and trade".