Art historians have questioned whether this watercolour is really a view of Dover. The work was probably made for an uncompleted project on the English Channel, intended to illustrate both the French and English coastlines. This may in fact be an unknown French subject rather than Dover.
Turner had almost stopped making studies for his watercolours by 1820. He preferred to begin and complete a work in several hours on the spot. This may be an early example of his new way of working as there are no known sketches for 'Off Dover'.