Lake Hamana is one of the largest brackish lakes in Japan and is located at the western end of Shizuoka Prefecture. It is connected to the Sea of Enshu-nada, a local name for the Pacific Ocean, through a 200 m wide channel named Imagiriguchi. The lake has a surface area of 69 km² and its coast stretches over a distance of 103 km. It has a water volume of 330,000,000 m³.

There are 3 cities, 6 towns and 1 village located within the Lake Hamana catchment basin which has a total area of 630 km². The lake is heavily subjected to tidal flows and, together with substantial freshwater inflow through numerous rivers and streams flowing into the upper part of the lake and a geographical formation of the lake consisting of numerous inlets, provides ideal habitats for aquatic flora and fauna. It has therefore been famous in fishery throughout history. There has been organized efforts made to transform the fishery industry to aquaculture industry. Much greater emphasis has been placed in recent years on culturing of sea weed Undaria pinnatifida, oyster, as well as on growing fingerling of Acanthopagrus schlegeli, Lateolabrax japonicus, Portunus (Portunus) trituberculatus, Penaeus (Melicertus) japonicus for local culturing and for marketing elsewhere.

Lake Hamana is also blessed with scenic spots and has been designated as a Prefectural Park. Its clean water, greeneries along the coastline, and rolling hills in the catchment area, are great assets for tourist industry. Geographically, it is located just about equidistant from eastern and western economic zones in Japan. Tomei National Highway system and Hamana-ko Lakesideway highway system, among other transportation systems, provide convenient access to the lake, making Lake Hamana even more attractive for promotion of tourism.