The present paper reviews the anthropogenic pressure related with freshwater resource availability and its exploitation through irrigation and damming in the Rufiji and Pangani river basins and their resulting impacts on the Rufiji and Pangani estuaries and adjacent coastal and marine habitats, located along the southern and northern coast of Tanzania, respectively. In the Rufiji River Basin, water abstraction for the existing and planned irrigation and hydropower developments have been estimated at 12,788 million m3, which is 45% of the total available 28,382 million m3 water in the Basin. In the Pangani River Basin, water abstraction for the existing irrigation and hydropower developments have been estimated at 810 million m3 which is 90% of the total available water (900 million m3) in the Basin. The reduced river flow due to irrigation and hydropower developments are considered to have significant environmental impacts on the estuarine and adjacent coastal and marine habitats. The environmental impacts are more severe during the dry season than during the rainy season. It is also noted that the two basins are generally at different levels of water stress, with the Pangani Basin being under more critical water stress compared to the Rufiji Basin.