Microplastics have emerged as a significant environmental concern due to their infiltration into freshwater and marine ecosystems. To address this challenge, the hydrocyclone has been investigated as a potential solution for separating microplastics from water. Utilizing strong centrifugal forces, the hydrocyclone effectively separates discrete phases, such as microplastics, from continuous phases. Furthermore, hydrocyclones offer flexible operation, high capacity, and low operation and maintenance costs. In this study, computational fluid dynamics (CFD) modelling was used to investigate the hydrodynamics and microplastic separation in hydrocyclones with different operating parameters to separate microplastics from water. From the computational result, microplastics were separated with 83.06% plastics recovery in case inlet velocity of 10 m/s and PET microplastics concentration of 0.1%vol. In addition, the ANOVA demonstrated that microplastic density and inlet feed velocity were significant factors affecting microplastic separation in the hydrocyclone.