Sailing Directions are written directions that describe the routes to be taken by boats and ships during coastal navigation and port approaches. There are also products known as Sailing Directions, which are books written by various Hydrographic Offices throughout the world. They are known as Pilot Books, because they provide local knowledge of routes and landmarks, which would typically be provided by a local marine pilot. As such, they are used frequently by naval and government vessels, who are exempted from 'Compulsory Pilotage' in many ports.

Many nations publish Sailing Directions for their home waters, where they are the International Hydrographic Organization's (IHO) primary charting authority. However, the most widely used Sailing Directions product is the United Kingdom Hydrographic Office's, 'Admiralty Sailing directions' (ASDs)( a.k.a. Pilot books). The ASDs, sold under the Admiralty brand, provide the most comprehensive geographic coverage of coastal routes worldwide. They are designed to supplement and enhance the data shown on British Admiralty Nautical Charts, by describing routes for seagoing vessels, relative to coastal features. Ocean routes are covered by the Admiralty book 'Ocean Passages for The World' (Abbrev. OPTW. Nautical Publication NP136), which describes Offshore routes separately for power driven vessels, and low powered / sailing vessels.