The study discusses the perspectives of long-term maintenance of Russian as a heritage language in Germany. Based on data from a longitudinal study (2014-2018) we investigated changes in the sociolinguistic situation of 19 adolescent heritage speakers and in their proficiency in Russian. The aim was to investigate whether changes in the participants’ sociolinguistic situation are reflected in their knowledge of Russian. Data on the sociolinguistic situation were collected via an extensive questionnaire that the participants had to fill out once a year. Language proficiency was measured by experimental tasks targeting different linguistic domains. For the current paper, we used data from the longitudinal measurement of lexical and grammatical proficiency. The results revealed that the participants’ exposure to Russian input is decreasing in several domains over time, especially concerning media consumption and personal visits to the homeland. Russian is increasingly restricted to interactions with parents, and to educational settings (classes in Russian as a foreign or heritage language). Regarding language attitudes, our participants explicitly consider Russian important primarily for family interactions and cultural factors, but less with regard to career goals. Nevertheless, there was a positive trend in lexical and grammatical proficiency. We interpret these findings as a result of the prolonged exposure to heritage language instruction which leads to a stabilized proficiency in Russian. Given the institutional support and the size of the community, we hypothesize that the perspectives for long-term maintenance of Russian as a heritage language in Germany are better than for Russian heritage speaker communities in other countries.