A deeper understanding of the spatial distribution of CO2 concentration inside cultivation facilities (e.g., greenhouses and plant factories) is necessary for the quantitative evaluation and/or the improvement in the performance and efficiency of artificial CO2 enrichment methods. We developed 3D computational fluid dynamics (CFD) models for two CO2 enrichment methods in a strawberry greenhouse – one was for overall greenhouse enrichment, as the usual method, and the other was for localized crop enrichment. We confirmed the model validation by comparing the simulated and measured CO2 concentrations in the greenhouse. With regard to the entire enrichment condition, CO2 accumulated at the upper part of the greenhouse through convection due to the high temperature of CO2 generated while there was low CO2 concentration around the crops. This could be regarded as an ineffectual situation. However, such situation can be alleviated by lowering the temperature of CO2. On the other hand, we found that crop-local enrichment can increase CO2 concentration only around crops albeit with less effect on those at the upper part. Thus, changing the enrichment strategy as well as the equipment could greatly optimize the distribution of CO2 in a greenhouse, thereby improving the efficiency of CO2 enrichment.