Navigation channels are a fundamental component of international maritime transport because they reduce costs and transit times, which in economic terms affect the competitiveness of international trade of countries. The two most important navigation channels are changing according to the times. Both the Panama and the Suez Canal have experienced expansion several times since their construction. Since the beginning of the present century, both have also undergone re-engineering to follow the rate of change of international maritime transport. Among other factors, such re-engineering had two impacts that are developed in this chapter: physical and commercial. The authors argue that the latest re-engineering followed similar patterns and that, within the market range in which both canals compete, the results can be analysed by the changes in the tonnage mobilized by each, with special impact on traffic between Asia and Europe and the east coast of North America. Among the significant differences that have arisen between the two canals are price structures and the method of measuring ships – topics therefore discussed in the chapter.