Under the customs warehousing procedure products can be regularly warehoused for unlimited periods in certain premises or other locations authorised by customs (customs warehouses) within the customs area of the Union.

No import duties become due, neither must any trade measures (such as showing import authorisations or import licences) be observed during storage in a customs warehouse.

Customs warehouses thus allow, on the one hand, products in transit to be warehoused within the Union without having to pay import duty, and, on the other, where products are intended to be sold in this Customs territory, that import duties are paid only after the completion of a warehousing period (credit function) or that the warehoused goods are placed under a different customs procedure.