Underwater friction stir welding (UFSW) is a modification of FSW where water is utilized for coolant to manage heat transmission and minimize defects in the weld joint. This review article presents an overview for the role of process parameters of UFSW and their impact on weld excellence, integrity, and properties. The presented review begins with discussion on the challenges related with traditional welding techniques such as cracks, voids, porosity, and poor strength. To deal with these challenges the importance of improved cooling rate and reducing the height temperature in UFSW. The effects of UFSW working variables as revolving speed, travelling speed, tool inclination angle, tool geometry, temperature of the cooling medium, and plunge depth are discussed. It explains that how these parameters affect heat production, materials flow, joint formation, presence of defects, and stability of process and compliance of different joining conditions. The article also focuses on the importance of optimization of parameters in UFSW for enhanced quality joints with the required mechanical properties and other joint performance. Additionally, exploration is essential to deeply investigate the effects of these parameters and their interactions in process of UFSW, especially in the aerospace aluminum alloys.