Direct proof of use
Open-source reporting placed Akula-class submarines in Russia's Syria-bound naval deployment in late October 2016. The Barents Observer reported that two Northern Fleet Akula-class submarines had joined the Russian naval battlegroup, while Forces News reported that Royal Navy and NATO tracking included two Akula-class submarines and a Kilo-class boat moving toward the Admiral Kuznetsov group.
The documented conflict role is fielding and deployment with Russia's naval force supporting the Syrian government and its allies. The sources reviewed for this record do not document an Akula-class submarine firing weapons in Syria.
Sources: Two nuclear submarines from Kola sail into Mediterranean, Russian Submarines 'Join Battle Group Heading For Syria'
Narrative
The Akula-class appearance in the Syrian war was part of Russia's larger 2016 naval demonstration around Admiral Kuznetsov rather than a separately documented submarine strike campaign. USNI News described the Northern Fleet deployment as bound for the eastern Mediterranean and tied to the Syrian war, and RFE/RL later reported Russia's announcement that carrier aviation had begun combat operations from the group.
The undersea component was reported shortly before the carrier group reached the eastern Mediterranean. Barents Observer identified the nuclear-powered boats as Akula-class submarines from the Northern Fleet and separately noted a Kilo-class submarine also sailing toward the Mediterranean. Forces News likewise described two Akula-class submarines and one Kilo-class boat being tracked as they moved toward the Russian fleet.
Public reporting on Russian submarine-launched strikes in Syria points to a different platform: the diesel-electric Kilo-class Rostov-on-Don, which fired Kalibr missiles from the Mediterranean in December 2015. That distinction matters for the Akula-class record: the Akula boats are documented as deployed with the Syria-bound naval force, while the available public sources do not identify them as launch platforms for strikes in the Syrian campaign.
Sources: USNI Kuznetsov Deployment Analysis, Two nuclear submarines from Kola sail into Mediterranean, Russian Submarines 'Join Battle Group Heading For Syria', Russia's Aircraft Carrier Launches First Strikes On Syria, Russian Submarine Hits Targets in Syria