Offshore Navigation (JN) (Formerly Junior Navigation) is the first of a two-part program in offshore (open coast) navigation. It is designed as a practical how-to-course. Subject matter includes: basic concepts of celestial navigation; how to use the mariner's sextant to take sights of the sun; the importance and techniques of accurate time determination; use of the Nautical Almanac; how to reduce sights to establish lines of position (LOPs) and the use of special charts, plotting sheets and other navigational data for offshore positioning and passage planning.

Although there are no prerequisite courses; however, successful completion of Boat Handling, Marine Navigation and Advanced Marine Navigation are required for advancement to the grade of Junior Navigator (JN).