Most of the pipelines used for the transport of various fluids are susceptible to the formation of biofilms, and the undesirable accumulation of microorganisms in pipelines leads to biodeterioration and increases the maintenance cost of the pipelines. This book focuses on nanostructured polymetallic coatings for corrosion and biofouling protection in offshore oil and gas pipelines, marine pipelines, ship structures and port facilities, and corrosion resistance surfaces of several engineered structures. Considering various reasons of biofouling in pipelines that transport crude and refined petroleum, gas, biofuels, and other fluids including sewage, slurry, and water for drinking or irrigation, the underlying mechanism is thoroughly explained. A comparison of various protective techniques is also highlighted for the choice of methods for specific applications.