Market demand for "clean and green" food products is increasing, and so there is growing opportunity for the seaweed aquaculture industry to take a position as a key food producer in this area. In this study, in order to investigate the impact of dry fractionation on seaweed protein qualities, dried and milled seaweed powder from three seaweed species was sieved into 6 fractions (F1 to F6) of different particle size from >710 mu m to 710 mu m) contained the highest protein and amino acid content in L. digitata. Glutamic acid was the most prevalent amino acid in A. esculenta and L. digitata (55.34 mg/g and 23.78 mg/g), while aspartic acid was the most prevalent in S. latissima (19.41 mg/g). This information is valuable to both researchers and seaweed producers who can use particle size separation as a simple method to create value-added products using their green biomass for applications across multiple markets.