Critical thinking is essential for young children and can be enhanced through appropriate and supportive curricula. With the rich affordance of digitalization, this study evaluated the effects of a hybrid STEM curriculum on critical thinking skills in 74 kindergarteners (42 boys and 32 girls) aged 5.83-7.25 years (Mean = 6.44, SD = 0.31) from a Chinese kindergarten during the COVID-19 pandemic. Employing a quantitative design across two classes, we collaborated with teachers, children, and parents to co-develop a series of STEM activities throughout an academic year. Despite the absence of a pre-test due to pandemic restrictions, no significant age differences or differences in their related assessments prior to participating in this study. Results showed that the experimental class demonstrated significant improvements in interpretation, explanation, inference, and self-regulation skills compared to the control group. These findings suggest the STEM curriculum effectively enhances critical thinking in early childhood education.