OBJECTIVE(S): To evaluate changes in injecting and sexual risk behaviours, and hepatitis C virus (HCV) reinfection incidence among people with HIV/HCV coinfection following unrestricted access to direct-acting antiviral therapy in Australia. DESIGN: Prospective observational cohort study (2014-2018). METHODS: Among people enrolled in the Control and Elimination of HCV from HIV-infected individuals within Australia study, changes in injecting and sexual behaviour were evaluated, including injecting drug use (IDU) in the last 6 months and last month, frequency of IDU and equipment sharing, condom-less anal intercourse with casual male partner(s), and group sex. HCV reinfection incidence was evaluated with follow-up through May 2018. RESULTS: Overall, 272 HIV/HCV antibody-positive participants [median age; 50 years, 96% male, 83% identified as gay and bisexual men (GBM)] had behavioural data at enrolment and follow-up (median 2.91 years) available for analysis. The proportion reporting IDU in the last 6 months remained stable from enrolment (35%) to follow-up (39%). Among GBM, the proportion reporting condom-less anal intercourse with casual partner(s) at enrolment (48%) and follow-up (46%) was also similar. Reinfection was detected in five individuals (all GBM) during total follow-up of 474 person-years for an overall incidence of 1.05 per 100 person-years (95% confidence interval, 0.44-2.53). CONCLUSION: No change was observed in levels of injecting or sexual risk behaviour for HCV infection following unrestricted access to direct-acting antiviral therapy in an Australian HIV/HCV cohort. Incidence of HCV reinfection was low potentially reflecting high levels of treatment coverage within this population. Continued screening and rapid retreatment of reinfection will be required to maintain progress towards elimination.