This study examines the effects of two pivotal maritime regulations, namely the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII), implemented by the IMO starting from 2023, on the container-fleet deployment. A mixed-integer programming model is formulated to optimize the fleet deployment with considering the constraints of the above-mentioned regulations and the goal of minimizing operating costs. The findings reveal that the CII regulation leads to a substantial decrease in both ship speeds and carbon emissions concurrently, although there may be an uptick in the number of deployed ships. Conversely, the EEXI has a minor effect on speeds due to the prevalence of slow steaming. Based on research findings, several policy implications are elucidated for shipowners.