Customs provisions may be contained in, and international customs cooperation organised through, international instruments with a regional or bilateral scope.
Those provisions and mechanisms may be part of agreements dedicated to customs matters (e.g. Agreements on Cooperation and Mutual Administrative Assistance in customs matters, or the Common Transit Convention); or of agreements with a broader coverage: preferential trade agreements (like Free Trade or Customs Union Agreements), agreements with a wider political but non-preferential purpose (like Partnership and Cooperation Agreements), or Association Agreements covering both.