A group of students taking the Service-Learning subject ‘Building Green Communities with Environmental NGOs’ organized the ‘PolyU Bring Your Own Bottle Day’ on 16 November 2018. Supported by the Ocean Park Conservation Foundation Hong Kong, these students arranged activities on campus to boost awareness of the University community on reducing reliance on disposables. Observations, surveys and interviews were conducted to assess and promote the bring your own bottle habit. Their project advocated the positive message on environmental education and invited like-minded people to join them and taking up the BYO habit.