Anyone who does all or most of their boating on our oceans, must have an intimate knowledge of the natural cycles of the tides, and the sometimes dangerous currents they can generate. This seminar cannot cover every detail of tides and currents, but is an overview of tidal basics and is an excellent primer for the Canadian Power and Sail Squadrons courses, Near Shore Marine Navigation Level 1 and Level 2. Inland waters, such as the Great Lakes do not experience tides, but there is a short section in the seminar dedicated to the “seiche,” a natural, irregular phenomenon, that causes tide-like changes in water levels in these waters.