Lake Hamana (浜名湖, Hamana-ko) is a brackish lagoon in Shizuoka Prefecture, Japan.

As an internal body of water, it is considered Japan's tenth-largest lake (by area).

Lake Hamana is a commercial source of cultivated Japanese eel, nori, oysters and Chinese soft-shelled turtles.

However, the 1498 Meiō Nankaidō earthquake altered the topography of the area and connected the lake to the ocean.

At the end of World War II two experimental Type 4 Chi-To tanks were dumped into the lake to avoid capture by Occupation forces.