It shipped a total of 7.2 million tonnes of crude oil and refined products in 2008, down from 9.5 million tonnes in the previous year.
The August rise was for a second consecutive month while the previous year-on-year falls came as some crude was re-routed to the Baku-Tbilisi-Ceyhan pipeline, which goes to Turkey, and as railway fees rose in neighbouring Azerbaijan.
Batumi receives crude and refined products by rail from Azerbaijan.
Some volumes are shipped across the Caspian Sea from Central Asia in small tankers, unloaded in the Azeri port of Baku and then sent by rail to Batumi for re-export to the Mediterranean.
Some are sent directly from ex-Soviet Azerbaijan by rail, including from the giant BP-led Azeri-Chirag-Guneshli project, mostly by U.S. oil major Exxon Mobil.
Kazakh state energy firm KazMunaiGas became the sole owner of the oil terminal in Batumi's port in February 2008 by buying stakes from its partners.