Long non-coding RNAs (lncRNAs) are important mediators of the initiation and progression of tumors, including breast cancer (BC). The exact role of long intergenic non-coding RNA 00312 (LINC00312) in BC and its mechanism of action have not been reported to date. In the present study, LINC00312 was found to be downregulated in human BC tissues and cell lines by RT-qPCR. The findings of a functional study indicated that overexpression of LINC00312 suppressed the proliferation, colony forming ability, migration and invasiveness of BC cell lines. Mechanistically, LINC00312 was found to induce suppression of cell migration and invasion by directly binding to miR-9. Overexpression of LINC00312 increased the expression of cadherin 1 (CDH1), a direct target of miR-9, and decreased the expression of vimentin (VIM), a major cytoskeletal component of mesenchymal cells as determined by western blot analysis. miR-9 partly abrogated the upregulation of CDH1 and downregulation of VIM induced by LINC00312. Taken together, the results of the present study indicate a role for the LINC00312/miR-9/CDH1 axis in the progression of BC, and suggest a novel lncRNA-based diagnostic biomarker or therapeutic target for BC.