This work presents the last contributions incorporated into AUV Guanay II, these have been emerged after some test fields, tests in the swimming pool and in the ocean, such as Mar Menor and Mar Mediterrani. These improvements are: First in the communication and control systems, for a more fluid communication a WiFi system has been incorporated, this allows access to PC-104 of Guanay II without disassemble it; second, a new RF system to connect and disconnect the electronics and a new method to charge the batteries have been designed; third, a new driver for lateral motor has been developed that allows control the motor in both directions; then the software of the vehicle and the base station has been upgraded to obtain a major and better user control; finally, a new ballast system has been incorporated. All of new contributions have been tested in the laboratory and in the field.