It was based in Noviodunum and controlled the Lower Danube from the Iron Gates to the northwestern Black Sea as far as the Crimea.
After Trajan's conquest of Dacia, during which the Classis Moesica provided logistical support, its base was moved back to Noviodunum.
The fleet also included several secondary ports, like Carsium, Novae, Oescus and Tomis (modern Constanta).
Military diplomas show that the classis Moesica belonged to the army of Moesia Inferior.
In Scythia Minor, during late Antiquity there were marines (muscularii)[5] of legio II Herculia at "Inplateypegiis" and sailors (nauclarii) at Flaviana.