Underwater target localization using several autonomous underwater vehicles(AUVs) is a challenging issue. A systematic and exhaustive coverage strategy is not efficient in term of exploration time: it can be improved by making the AUVs share their information and cooperate to optimize their motions. Communication points are required to make underwater vehicles exchange information: for that purpose the system involves one autonomous surface vehicle (ASV), which helps the AUVs to re-localize and to exchange data, and two AUVs that adapt their strategy according to gathered information, while satisfying the associated communication constraints. Each AUV is endowed with a sensor that estimates its distance with respect to targets, and cooperates with others to explore an area with the help of an ASV. To provide the required autonomy for these vehicles, we built upon an existing system with additional components, which provides an embedded planning and execution control framework. Simulation results are carried out to evaluate the proposed architecture and adaptive exploration strategy.