This study aimed to investigate the effects of STEM-based activities on grade 5 students' science learning achievement, computational skills, and satisfaction with the learning experience. The study involved 30 grade 5 students in the Thai context, and data were collected through a learning management plan designed using STEM-based activities, a learning achievement test, a computational thinking test, and a satisfaction questionnaire. Mean scores, standard deviation, and a paired samples t-test were used to analyze the data. The results showed that STEM-based activities had a positive impact on grade 5 students' learning achievement and computational thinking skills. Moreover, the students expressed a high level of satisfaction with the STEM-based activities, which provided an engaging and relevant learning experience. These findings contribute to the growing body of evidence supporting the effectiveness of STEM-based activities in promoting student achievement and satisfaction with the learning experience.