Avacha (Russian: Авача) is a river in the southwestern part of the Kamchatka Peninsula, Russia. It flows southeast into Avacha Bay. The river has a length of 122 km and a watershed of 5,090 square km. Nineteenth century travelers like George Kennan (explorer) ascended the Avacha as far as possible and then took horses to the upper Kamchatka River to travel further north.
The town of Yelizovo, which houses the Petropavlovsk-Kamchatsky Airport, is located on the banks of the Avacha River.