The modern era necessities and overuse of non-renewable energy by mankind have depleted the natural resources to a scaring extent. The effect of water depth to the FPSO response is an important aspect to be investigated, as today, new floating structures are being installed in deep waters of up to 3000m depth. Hence in this paper, a study on the effect of FPSO response by varying the water depth has been presented by conducting model tests in the Offshore Laboratory, Universiti Teknologi PETRONAS. The results give an insight on the variation of surge, heave and pitch responses of the FPSO and mooring line tensions to the varying water depth. The results show an increase in the response as the water depth is increased and it is finally concluded that for minimizing the FPSO motions, the mooring line tension has to be increased as the water depth increases. © 2016 Taylor & Francis Group, London.