This paper presents a clear-cut research on how PBL was employed. This contributes to the realistic environmental application by equipping learners in addressing environmental vulnerabilities and threats, which are often compounded to economic devastation. It was an exploratory qualitative research design which employed a case-study method. This study reveals that PBL has a sustainability mechanism once used as advocacy for environmental conservation. The utilization of this endeavour has a strong force to the holistic learning of the students. Likewise, it contributed directly in developing students’ values in line with environmental sustainability through the preservation of communities’ sensitive areas. This is said to be one of the major keys in attaining environmental conservation, since it incorporates economic, environmental and inter-generational learning.