In this chapter, we focus on automata-based representations of hybrid systems [1,2] and address the problem of representing faithfully situations where a hybrid automaton exists within an environment and derives information about other automata by observing the environment itself, rather than by using any form of direct communication. We call this kind of communication implicit. The main sources of motivation for these studies are real applications presented in the European project C4C, such as agents performing a search mission, e.g., UAVs [3] or autonomous underwater vehicles [4], but also road traffic problems [5,6] and autonomous straddle carriers in harbors [7]. In all these situations, we have a collection of agents that need to communicate and coordinate to achieve a common goal; hence, distributed systems. Moreover, the agents move within an environment that changes dynamically and detect each other's presence not necessarily via direct communication but rather by observations of the environmental changes. Current techniques for modeling similar cases are not able to represent in a realistic and natural way the ability of each agent to take autonomous decisions, based only on its perception of the surrounding environment. This implicit communication is needed when direct exchange of information is not possible, unreliable or forbidden. Instead of providing the system with an omniscient machine, we decided to copy the nature and exploit sensors embedded in each agent. Since we need to satisfy compositionality properties, due to the multi-agent nature of the case studies, we start from the Hybrid I/O Automata (HIOAs) [8] representation and add some features to model their interaction with the environment. We will show how to apply our framework to the following example