Conventional pile materials, such as steel, concrete, and wood, can encounter serious corrosion problems in industrial and marine environments. Deterioration of steel, concrete, and wood piling systems has cost the military and civilian marine and waterfront civil engineering communities billions of dollars to repair and replace. Fiber-reinforced polymer (FRP) composites have desirable properties for extreme environments because they are noncorrosive, nonconductive, and lightweight. Different types of FRP composite piles are currently under research investigation, and some have been introduced to the marketplace. FRP composites have been used as internal reinforcement in concrete piles; as external shells for steel, concrete, and timber piles; and as structural piles such as FRP pipe piles, reinforced plastic piles, and plastic fender piles. The different ways of constituting FRP composite piles result in different behavioral effects. Because FRP structural piles have anisotropic properties, low section stiffness, and high ratios of elastic to shear modulus, they have different behavior in load-displacement relations under vertical and lateral loads. Current design methods for conventional piles were examined to determine the validity for FRP composite piles, and some new design methods specific to FRP structural piles were developed from research work conducted by the authors.