Customs has to deal with a massive number of containers arriving at ports. This massive flow of cargo provides an opportunity for organized crime infiltration. Risk management and the security of the supply chain has become a top priority for Customs administrations and for private firms. In this paper, we develop models that allow Customs to optimize its inspection process to target high-risk containers without hindering the flow of safe containers with extra delays at ports. The model characterizes optimal informational and physical inspection rates as a function of the risk factors attributed to containers. We use this model to analyze how an effective public–private partnership for risk and security management can be established between Customs and private firms.