Water is very essential for all living beings. It covers nearly 70% of earth's surface. Even though the major portion of earth is covered by water, there is severe shortage of drinking water in most of the countries across the world. Safe drinking water is vital for all forms of life though it does not provide any calories. Desalination of sea water appears as a solution for this problem. Advanced desalination technologies that are applied to seawater and brackish water prove to be effective alternatives in a variety of situations. This study mainly focuses on upcoming trends in modern desalination technologies and emphasizing the options offered by them. Desalination is a technique where the excess salts are removed from sea water or brackish water converting it into safe potable or usable water. Desalination methods are categorized into thermal processes and membrane processes. In this chapter we discuss about different thermal processes like multistage flash distillation, multiple effect distillation, vapour compression evaporation, cogeneration and solar water desalination. We also discuss about various categories of membrane processes like reverse osmosis, electro dialysis and membrane distillation methods. This chapter also concentrates on advantages and disadvantages and economical parameters involved in each of these methods.