This paper describes remotely operated vehicles and the preliminary experiment results for system identification. The robot used in this study is a remotely operated vehicle that is under development by Korea Research Institute of Ships and Ocean Engineering. It is controlled by eight thrusters and is equipped with an inertia measurement unit, Doppler velocity log, pressure sensor, light emitting diode lighting, and analog camera. This paper presents the results of the towing test and free floating experiment in a water tank for system identification of the remotely operated vehicle. The proposed system identification method determines the dynamic parameters of a vehicle to design a controller for precise control. The proposed method can obtain 2-degrees-of-freedom model parameters for the vehicle.