The Fujairah plant is the largest desalination hybrid plant in the world. The water production is 454,000 in m(3)/d, 62.5% from 5 MSF units coupled with the power plant and 37.5% (170,500 m(3)/d) from seawater reverse osmosis. This concept provides a more flexible system as the RO system helps to sustain the electricity demand when there is a mismatch between the water and electricity demand. Degremont was selected to design-build-commission the RO part, the largest SWRO ever built. The precise definition of the plant proposed by DEGREMONT was linked to the results of a 9 month pilot-plant trials to verify both the raw seawater quality and the performances of the foreseen pre-treatment. After two years of construction, the plant was successfully commissioned in September 2003. It was operated at reduced capacity (approx. 30%) during the first year of operation due to the one-year delay experienced for the completion of the external projects of the gas and treated water pipelines as well as lack of treated water demand. In the second year the RO plant started to run at full capacity. The water produced is sent to 200 kin south west for irrigation purpose in the Al Ayn region (Emirate of Abu Dhabi). The Fujairah SWRO plant with a production capacity of 170,500 m(3)/d during 3 years has been the largest RO operating plant ever built in the world. Equipment delivery, plant erection and commissioning were achieved within a very tight schedule. The objectives of this presentation are to present the main operational results of the Fujairah SWRO plant over the first 2 years of operation and the resulting practical design and operational recommendations for future plants.