With 30% of the countries of the world facing high level of water stress, the problem of fresh water scarcity needs to be tackled. Since saline water represents 97.4% ofthe water of the Earth, desalination is one of the main resources that can be used to mitigate the water shortage. In this review, the four main technologies belonging to the different separation processes (membrane, thermal and hybrid processes) in desalination are analysed through the scientific desalination literature and throught he data collected of more than 1,300 real desalination plants. Reverse Osmosis (RO-membrane process) is the most dominant technology with a capacity share of the 70%.