In the last years, with the flourishing of the WSN (wireless sensor network) paradigm, the monitoring and exploration of the terrestrial environment has greatly improved. While terrestrial and aerial WSN applications have been developed, the aquatic world has been unaffected by this revolution, although WSN could play an important role in the underwater framework as well. This is mainly due to the intrinsic difficulties in transferring the conventional WSN know-how to the aquatic world: in particular, communication issues arise, as radio waves are remarkably attenuated and acoustic communication is unfeasible because of its low propagation speed. In this paper, we present an innovative proposal for a Smart Underwater WSN, where optical communication systems are exploited for creating the network among the nodes. A simulator has been developed with the aim of helping the design of the network nodes and find the best solution in terms of communication quality.