This presentation compares conventional and membrane technologies for the pretreatment of Seawater Reverse Osmosis (SWRO) systems. The variability of open intake seawater feed sources creates a demand for superior RO pretreatment. UF/MF pretreatment consistently produces RO feed water of superior quality, regardless of the raw water quality. The benefits of UF/MF to SWRO allows for operation at higher flux and the ability to capitalize on higher permeability membranes.