Karymsky Lake (Russian: Карымское озеро) is a volcanic crater lake located in the Akademia Nauk volcano on the Kamchatka Peninsula, Russia.

On midnight of 2 January 1996, Akademia Nauk and Karymsky Lake erupted.

Eruptive pulses from the bottom of Karymsky Lake ejected steam and ash columns in the air every five to six hours for the 18 hours that followed, releasing approximately 30 to 40 million tons of highly acidic pyroclastic material in the air, tsunamis up to 20 meters (65 feet) also occurred.

Much of the material, which was rich in sodium, sulfates, calcium, and magnesium, collapsed back into Lake Karymsky, changing its pH from 7.5 (neutral) to 3.2 (moderately acidic).

The pH of Lake Karymsky had returned to neutral (7.54) by 2012, but it was still three times saltier than prior to the 1996 eruption.