Reverse osmosis is a very energy-efficient approach for seawater desalination. Since it requires only electrical energy, a combination of reverse osmosis and photovoltaic (PV) plants seems to be a promising solution. Therefore, a PV-based reverse osmosis plant for seawater desalination for a location in Saudi Arabia is designed and modeled. On this basis, different options of a PV-powered seawater desalination plant are investigated and conclusions for the construction of such plants are derived.