This book describes some approaches for developing the numerical models to efficiently predict the formation of extreme waves which can pose a threat to the safety of marine structures.The numerical algorithms for solving different governing equations and the theoretical probability models for extreme wave predictions are explained in detail.These models can help engineers in the design of marine structures that can withstand extreme waves. With more frequent extreme weather due to climate change, extreme waves have become more common.Extreme waves are an interesting phenomenon, but because of their enormous destructive power, understanding their formation mechanism, properties, and impact, is necessary for the design and safe operation of ships and offshore structures.