The aim of this paper is to review the available simulators defining in a first step the necessary requirements to cope with the multi-vehicles cooperation context. In order to get a complete overview of these tools, a new classification is proposed and is used to sort the existing simulators. It is worth to be noted that we focus our interest on simulators which can at least address the problem of marine robotics. None of the available simulators being compliant with the previous requirements, a new simulation architecture is proposed. Thetis is a real-time multi-vehicles hybrid simulator for heterogeneous vehicles. This simulator allows Hardware In The Loop (HIL) simulations including the use of virtual sensors which allows to provide a representation of a virtual world, and includes the support of communication devices. The included acoustic propagation model allows communications between the vehicles. Finally some simulation results involving one or more AUV (Autonomous Underwater Vehicle) and/or USV (Unmanned Surface Vehicle) are presented.