This paper presents a comparative analysis of the linguistic landscapes (LL) of two distinct ethnic areas in Shin-Okubo, Japan: Koreatown and Islamic Street. By paying particular attention to the difference in the formation of the two immigrant communities, this study aims to better understand various functions of language on signage and their impact on socio-cultural interactions between immigrants and the host society. The findings reveal distinct functions of languages in the LLs, showcasing their significance to the dynamic process of immigrant community formation. In Koreatown, a major centre of Korean culture consumption among the Japanese, the symbolic use of Korean asserts authenticity and offers Japanese tourists an exotic experience. This creates a cohesive space of commodification, vitalising the area in harmony with the local host community. In contrast, Islamic Street represents a multifaceted space shaped by a diverse array of languages and scripts, reflecting its recent emergence of ethnolinguistic vitality. The LL of Islamic Street, characterised by the informational use of language that caters to the daily needs and transnational practices of immigrants, reflects and fosters their social and cultural distance from the host society.