<![CDATA[Environmental education plays a crucial role in preparing students to face increasingly complex life challenges. However, classroom-based instruction may provide limited opportunities for students to engage directly with authentic environmental problems. A living laboratory offers a contextual learning environment that connects real-world environmental issues with collaborative and field-based learning. This study aimed to examine the implementation of collaborative environmental learning through a living laboratory on sand mining issues and the improvement of university students’ environmental problem-solving skills (PSS). A quasi-experimental method with a one-group pretest-posttest design was employed. The participants were 40 undergraduate students enrolled in environmental-related courses and selected through cluster random sampling. Learning activities were conducted in the sand mining area of Bukit Sepuluh Ribu, Tasikmalaya, Indonesia, through five phases: problem orientation, field investigation, collaborative environmental analysis, solution design, and reflective evaluation. Data were collected through environmental problem-solving tests, observations, field documentation, and students’ reflective notes. Quantitative data were analyzed using descriptive statistics, normalized gain (N-gain), and a paired-samples t-test. The results showed an improvement in students’ PSS, with the mean score increasing from 50.13 (SD = 2.79) in the pretest to 83.28 (SD = 2.05) in the posttest. The mean N-gain was 0.67, indicating moderate improvement. The paired-samples t-test showed a statistically significant difference, t(39) = 251.51, p < 0.001, with a very large effect size (Cohen’s dz = 39.77). These findings indicate that natural laboratory-based learning enables students to investigate real-world environmental conditions and collaboratively develop solutions to the associated problems]]>
