Offshore Croatia is a relatively underexplored area with no oilfields currently on production. Exploration commenced in 1970 and several biogenic gas fields were subsequently discovered producing from shallow Plio-Pleistocene reservoir rocks in the northern Adriatic area; however, exploration wells drilled for oil in Mesozoic carbonates have failed, although several wells encountered oil shows. Using data from the Croatian and Italian Adriatic, we provide in this paper some new insights into the Mesozoic palaeogeography and hydrocarbon plays of offshore Croatia. Offshore Croatia has been divided into three areas - north, central and south - with distinctive geological characteristics and hydrocarbon systems. The effects and importance of halokinesis in the eastern Adriatic is described and its influence on the petroleum systems is discussed. The evaluation of a modern, regional, high-resolution dataset has enhanced our understanding of the Adriatic Basin and supports the presence of petroleum systems with potential mature source rocks in shales from the Triassic succession, supplying reservoir rocks in Jurassic and Cretaceous carbonate platform margins/slope talus plays, and Cenozoic siliciclastic plays.