RAB10, a member of the small GTPase family, has complex biological functions, but its role in breast cancer (BC) remains unclear. The aim of this study was to investigate the relationship between RAB10's role in BC, its biological functions, and BC prognosis. An online database was used to analyze the correlation between differential expression of RAB10 in BC and prognosis. The results of immunohistochemical assays in clinical cohorts were combined with the database analysis. The chi-square test and COX regression were employed to analyze the correlation between RAB10 and pathological features of BC. MTT, Transwell, and wound healing assays were conducted to detect BC cell proliferation, invasion, and metastatic ability. Bioinformatics techniques were employed to explore the correlation between RAB10 and BC tumor immune cell infiltration, and to speculate the biological function of RAB10 in BC and related signaling pathways. Our findings suggest that RAB10 expression is elevated in BC and is associated with HER2 status, indicating a poor prognosis for BC patients. RAB10 can promote the proliferation, migration, and invasion ability of BC cells in vitro. RAB10 is also associated with BC immune cell infiltration and interacts with multiple signaling pathways. RAB10 is a potential biomarker or molecular target for BC.© 2023. Springer Nature Limited.