At the beginning of 1916, the Caucasus was the only theatre of operations of the Great War from which good news for the Entente were coming. The Russian Caucasus Army successfully advanced on Erzurum and captured this Turkish fortress in early February. In February 1916, the forces of the Russian Caucasus Army’s right flank group started an offensive along the southern coast of the Black Sea. It soon became clear that the main factor of its success will be naval support. Mountainous territory and the absence of roads made the Army entirely dependent on the Russian Navy. It provided the land forces with artillery support, logistics, communication and reconnaissance. Even tactical maneuvers were not possible without the Navy: the only way to envelop a Turkish defensive line was to land troops in its’ rear. The Russian Black Sea Fleet managed to establish an effective system of communication and coordination with the advancing army units, helping them reach their goals. This is one of not well-known examples of the dominant role of naval support in the success of the army offensive. In this article, the author examines the scope and forms of interaction between the Army and the Navy in order to demonstrate how the warfare conditions could force to overcome traditional mistrust and misunderstanding of the two Services.