In all fields of research, scientists around the world consider metallic corrosion as a serious problem. In addition to being attacked by various bacteria, exposed metallic surfaces are also susceptible to corrosion under acidic or alkaline conditions. A material having distinguishing qualities including high specific surface area, high porosity, and desired surface functionalization is inexpensive activated carbon (AC). The chapter discusses the types and preparation and production methods of AC. This chapter also reviews the use of AC in metal corrosion prevention. Due to problems with its solubility in aqueous media and the use of harsh experimental conditions needed to functionalize it, there is little research on the anti-corrosion applications of AC.