The identification of specific biomarkers is essential to improve cancer therapy, and circular RNAs (circRNAs) have great potency to be biomarkers. We harbor the goal to unveil the role of circ_0104206 in colon cancer (CC). The relative expressions of circ_0104206, miR-188-3p and CCNA2 in different groups were studied using real-time quantitative PCR (qPCR) or western blotting. The proliferative and migratory capacity of cancer cells were monitored via CCK-8, colony formation and Transwell assays. The transplanted tumor models were generated to analyze circ_0104206's role in vivo. The putative relationship between miR-188-3p and circ_0104206 or CCNA2 by bioinformatics tools was testified through dual-luciferase or RIP assay. The abnormal elevation of circ_0104206 expression was observed in CC. Circ_0104206 silencing repressed CC cell proliferative and migratory behaviors, and also decelerated tumor development in animal models. MiR-188-3p was directly targeted by circ_0104206, and its inhibitor had the ability to reverse the anticancer effects of circ_0104206 silencing on CC cells. CCNA2 was a target downstream of circ_0104206/miR-188-3p network. Moreover, the repressive effects of CCNA2 absence on cell proliferation and migration were attenuated by miR-188-3p inhibitor. In conclusion, Circ_0104206 plays oncogenic roles in CC via the implication of miR-188-3p/CCNA2 network, which further discloses CC pathogenesis and supplies potential markers for CC.Thieme. All rights reserved.