Larnaca desalination plant is currently within the 10 largest SWRO plants in Europe. It has an installed capacity of 54,000 m(3)/d with product water conforming to WHO and EU drinking standards with innovative features such as 8 elements per pressure vessel and fully automated plant operation control. The plant is now in its 6th year of successful operation meeting all its contractual requirements on energy consumption, water quality and water quantity. The plant operation strategy was to initially make the plant efficient, thus improving the plant processes to reach optimum operational conditions, and subsequently operate the plant effectively i.e. sustain a stable and efficient plant operation, achieving continuously the targeted plant performance. The consecutive steps carried out in order to achieve the above were: Optimizations of process plant units Standardization of plant activities, and Stable plant operations This paper describes: (a) the process units and the main optimization that was carried out; and (b) the results of the stable plant operation achieved and the general plant performance over the last 6 years. The paper also describes the time schedule for the implementation of the above consecutive steps which was the basis for the sustained plant performance. Finally the paper concludes with generic steps of how to achieve efficiency followed by effectiveness in desalination plants.