Seaweed is rich source of natural bioactive compounds that could be exploited as functional ingredient for cosmetic applications. The aim of this study was to evaluate the biochemical compositions and bioactivities of 10 seaweeds collected from coastal waters of Vietnam. The present study also prepared and evaluated cream mask from mixture of seaweeds extracted with water. The results showed that Caulerpa lentillifera, Sargassum crassifolium, Ulva reticulata, and Kappaphycus alvarezii are potential rich sources of protein, polysaccharide, carotenoids, and vitamins with high antibacterial, cell proliferation, moisture retention, and tyrosinase inhibitory activities. Physicochemical analysis of cream mask from a mixture of these seaweed extracts indicated that it is yellowish brown in color with a specific odor of seaweed, stable, and homogeneous for up to 12 months of storage, with a pH of 6.1, and high spread and adhesive abilities. No total aerobic mesophilic microorganisms, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and heavy metals were detected in the seaweed mask cream. The seaweed cream mask was safe and caused no irritation to normal human skin, and it satisfied provisions of Circular No. 06/2011/TT-BYT dated January 25, 2011 of the Vietnam Ministry of Health, providing cosmetic management for the cosmetic products with anti-aging and moisturizing effects.