Nowadays, the Polish Old Believers live in a language island. Language islands are detached from their ethnolinguistic roots and suffer a constant shortage of language structures. On the one hand, they acquire the language of the dominant group; on the other hand, it is important for them to preserve the language of their ancestors. The Old Believers’ Russian dialect has been influenced by the Polish language for over a century. As a result of the territorial proximity of the Old Believers’ homeland with the compact Belarusian language territory as well as exposure to Belarusian language and its dialects, “Polish” Old Believers’ speech bears many features characteristic for them. The main aim of this paper is to present the prepositions of space in the local dialect of Old Believers in Poland and to describe their characteristics. The “Polish” Old Believers’ narratives investigated in this paper contain many examples of use of the prepositions of space typical for their indigenous dialects as well as the Belarusian language and dialects. There are also many examples of use of such prepositions that can be considered as a result of Polish influence on the Russian dialect of Old Believers living in Poland.