Volcanic lakes are of particular interest to geomorphologists and other professionals due to the diversity of the basins forms and the very dynamic development of lake systems. The origin and evolution of these water bodies are closely related to active volcanic and post-volcanic processes, they are characterized by rapid changes of shape, level, composition of water and characteristics of the coast. Usually bounded by craters, calderas and in the immediate vicinity of volcanoes, these lakes present a kind of by-product of volcanism. In the Kuril-Kamchatka region, two types of lakes can be distinguished: 1) dynamically developing young, some of them ephemeral, located on active volcanoes, in active craters. In these lakes, as a rule, there are active gas-hydrothermal manifestations, and their waters are highly mineralized; 2) stable (relict) lakes in the calderas of dormant and extinct volcanoes. Lakes of this type usually do not have explosive funnels or active gas hydrotherms, and the water in them is slightly mineralized. It suggests a much more ancient age and the decreasing of post-volcanic activity in caldera depressions. Lakes of different types can exist close to each other and form a single communicating systems.