Global water scarcity is increasing day-by-day due to population explosion, urbanization and rapid industrialization. Inevitably, surface water is widely contaminated by various hazardous geogenic, organic and inorganic contaminants, also by untreated industrial effluents and unscientific human activities. On the other hand, the rapid worldwide increase in consumption of petroleum products has inspired researchers to develop renewable and sustainable materials for water purification applications. Significantly, biomass-derived materials are promising substitutes for depleting resources. Specifically, marine-based biomaterials, for instance, chitin/chitosan, seaweeds and seaweed-based polysacharides (agarose, alginate, cellulose, carrageenan) are abundant, environmentally friendly, and renewable biomaterials that are considered an appropriate solution for environmental contamination. Over past few decades various studies have focused on marine-based and seaweed-polysaccharide-based composites because of their renewability and sustainability for water purification. A number of reviews exist for biopolymer-based material applications in water purification; but to promote marine-derived biomaterials for water purification, a critical review between conventional materials and emerging approaches using seaweed-derived materials is needed. Hence, the present review study is the first of its kind, shedding light on the selection of diverse marine-derived biomaterials, as well as their important physical and chemical properties, in order to design functional materials for water purification applications. Further, the present review critically assesses the high-performance marine-derived functional materials exploited for existing state-of-the-art water purification technologies. Marine-derived materials with unique properties, such as inbuilt functionality, high mechanical strength, and prominent surface area and their prominence in developing high-performance sustainable materials for water purifications are reviewed. Furthermore, the review also discusses the various methodologies developed for the preparation of multifunctional carbonaceous materials using marine-derived biomaterials. Such biochar compete with commercial activated carbon and graphene owing to their unique properties. Also, the challenges in implementing the developed functional biomaterials in state-of-the-art water purification technologies and future prospects are discussed.