This chapter describes techniques for intra‐ Wireless Sensor Networks (WSN) sensor and mobile sensor cooperation, as well as techniques for coordination across mobile entities and WSNs. It extends our system model progressively and covers the broad spectrum of popular WSN system classes. The chapter illustrates how a WSN instruments the real world for users and provides for core primitives within the ubiquitous and pervasive computing paradigm. It investigates the inter‐sensor cooperation for provisioning the desired Quality of Information (QoI) in static networks. The chapter considers the deployment of mobile assist nodes that cooperate with the multiple static sensor nodes in order to enhance the functionality and dependability of WSN systems. It shows that additional cooperation between the mobile assist nodes improves WSN performance while allowing for novel transaction‐based functionalities. The chapter discusses cooperation between different WSN systems.