The Union Customs Code (UCC) was adopted in 2013 and its substantive provisions apply from 1 May 2016 so as to align EU customs legislation with the requirements of the Lisbon Treaty. It replaces the Community Customs Code (CCC). The UCC was amended by Regulation (EU) 2016/2339, which modified Article 136 relevant to goods that have temporarily left the customs territory of the Union by sea or air.

The UCC was also amended by Regulation (EU) 2019/474, which introduced some technical amendments in Articles 34, 124, 126, 129, 139, 146, 272 and 275 UCC. It also introduced a new Article 260a to provide relief from import duties on goods repaired or altered in the context of international agreements. The UCC was also amended by Regulation (EU) 2019/632 allowing customs authorities and economic operators to continue using transitional arrangements (i.e., existing IT systems or paper-based arrangements) for the completion of a small number of customs formalities, until 2025 at the latest when new or upgraded IT systems for the completion of those formalities will be in place. In addition to the UCC, the European Commission has published delegated and implementing regulations on the actual procedural changes. The UCC Delegated Act has been modified regularly, in order to better implement the main rules established in the UCC and adjust them to the needs of economic operators and customs administrations.

There are a number of changes in the revised customs policy which also require an integrated IT system from the customs authorities. In April 2016 The European Commission published an implementing decision (number: 2016/578) on the work program relating to the development and deployment of the Electronic Systems of the UCC.