Abstract: A timing mechanism having a tide indicator including a window in its dial. Under the dial is placed a flat annular wheel fitted with two signs or indicator markings which appear in turn in the window. Around the edge of the window are additional indicator markings which enable one to estimate the time until the next tide. High tide is shown when one of the appropriate signs is situated at the top of the window, and low tide when it is at the left or right thereof. The annular wheel is guided by a semicircular plate around which it slides. It is driven by a toothed wheel fixed on a motion work of the watch movement. The toothed wheel activates a gearing fitted around the internal circumferentce of the annular wheel.