This research aims to compare creative problem-solving skills and study the creative problem-solving process of learners before and after playing Go Game during activities outside the classroom. The sample group was 21 undergraduate students from the Faculty of Humanities and Social Sciences, Phetchaburi Rajabhat University who registered in the second semester of 2024. The statistics that were used for analyzing data consisted of Means, Standard Deviations, and Dependent Sample t-test. The research results indicated that creative problem-solving skills of learners who played Go game during activities outside the classroom were evidently higher than before playing Go game during activities outside the classroom at .01, statistically. Creative problem-solving skills of the learners after the experiment was still significantly high with the higher scores. Regarding the difference of score levels, this indicated that all sub-skills in the creative problem-solving process of the experimental group showed positive development. All sub-skills possessed higher score level. The skills of selecting problem-solving methods and testing hypotheses had the highest increase in scores. This suggests that playing Go during activities outside the classroom can significantly develop learners' creative problem-solving skills.