A navigable waterway is a designated or commonly used pathway accessible to ships or boats of any kind. It may include routes across open water as well as riverways and canals that are accessible to boats. Sections of a navigable waterway may include dry areas such as portages or lifting devices (e.g. ship elevators or canal inclined planes).

The navigable route can cross open water or follow a confined channel. Designation or common use establishes the pathway rather than a requirement for continuous constructed banks.

Dry transfer sections can belong to the route where boats pass by portage or a lifting device. A ship elevator can therefore form part of a waterway despite physically lifting vessels between water levels.