The WCO–UPU Postal Customs Guide is a joint WCO–UPU tool, for Posts and for Customs administration staff dealing with Customs clearance of postal items. For Posts, it is intended as a means of acquainting staff with the various aspects of the postal supply chain's Customs component and with the different WCO standards, instruments and tools. For Customs administrations, the Guide helps staff responsible for Customs clearance of postal items to become more familiar with the postal processes involved in the international exchange of mail, particularly in view of the recent emergence of automation and dematerialization possibilities offered by electronic advance data (EAD) exchange, enabling enhanced risk assessment based on data and improved fiscal processes.

The Guide is also intended to form a common basis for dialogue and discussion at the national level between the designated operators (DOs) of Universal Postal Union (UPU) member countries and WCO Member Customs administrations.

The updated WCO-UPU Postal Customs Guide 2024 provides effective and up-to-date guidance on cooperation between Customs administrations and DOs, including: incorporation of recent work advanced under the WCO–UPU Contact Committee; incorporation of recent amendment/revision of the WCO and UPU Conventions, tools and guidelines; and, reflection of recent changes in the environment in which Customs processing of postal items takes place, e.g. EAD and e-commerce.