Thermal sprayed marine coatings in the marine environment usually encounter chloride-induced corrosion and microbiologically induced corrosion. Formation of microbial biofilm is crucial for subsequent attachment of large fouler and understanding the initiation and growth of the biofilm is essential for possibly controlling the occurring of biofouling. This paper reports the formation of Bacillus sp. bacterial biofilm on arc sprayed aluminum coatings and its effect on the corrosion behaviors of the coatings. Results show fast and pronounced attachment and colonization of the bacteria on aluminum coatings. The bacterial biofilm was systematically examined by CLSM, FESEM, and Raman spectroscopy. Electrochemical assessment revealed that the aluminum coating immersed in the bacteria-containing media showed higher corrosion resistance than the sterile samples. A model was proposed to explain how the microorganisms and their metabolic by-products protect the coatings against penetration of corrosive media. The results would give insight into design and fabrication of thermal sprayed coatings for enhanced anti-biocorrosion performances in the marine environment.