The religious and liturgical customs (Heb. minhagim) of the Jewish Community of Helsinki were codified in 2001 as the long-time rabbi Moshe Edelmann compiled an extensive manual called The Traditional Order of Synagogue Service in the Jewish Community of Helsinki. In the preface of the manual Edelmann notes that this tradition has been passed down from generation to generation from the Cantonist Jewish soldiers who established the community. Our paper focuses both on the historical origins and the present state of this so-called minhag Finland. How can these customs be described today against the changes and challenges set by the fluctuating religious landscape of 21st century Finland? Furthermore, in the study of minhag Finland, various historical and societal aspects and intra-Jewish developments in the European context must be taken into consideration, e.g. influences from different regions (Eastern Europe, Scandinavia, later on Israel) and from various ideological and theological movements (Hasidism, Zionism, Orthodoxy, Reform). Interreligious relations, mixed marriages and encounters with secular society – analysed in the other case studies presented in the session – have also had a crucial impact on the development of the customs.