Plastic pollution has become a major global conservation challenge. To reduce the generation of plastic waste, we designed and tested several behavioral interventions in a randomized control trial to reduce plastic waste in a high-rise office building. We randomly assigned eight floors in the building to four conditions: (1) simplified recycling signage, (2) signage with a marine animal trapped in plastic debris, (3) signage with a pledge that invited people to be plastic wise to protect ocean life, and (4) control. We found that the signage with the animal reduced plastic waste by 17%, the largest effect among the other conditions. After implementing the signage to the entire building, we found an overall reduction in plastic waste over 6 weeks. The current study demonstrates the effectiveness of visualizing marine consequences of plastic waste and provides a behavioral solution connecting disposal actions and the downstream consequences for plastic waste reduction.