Records of Cretaceous marine snakes from Bosnia and Herzegovina have been known for nearly a hundred years. This paper presents a new finding of a pachyostotic snake from the local quarry Dubovac, three kilometers northwest of Bileća. The specimen consists of 29 vertebrae, seven of which are detached from the slab. The two best preserved vertebrae are almost square-shaped resembling Simoliophis rochebrunei but neural arches are much more swollen. Vertebrae and ribs are extremely pachyostotic as in Pachyophis woodwardi. Since there are no three-dimensional vertebrae of this species preserved from Bosnia and Herzegovina, precise identification was limited to a certain extent.