Nature experiences benefit human wellbeing by, for example, increasing subjective restoration and positive affect while reducing negative affect. However, natural environments are threatened by several crises, including pollution. In three preregistered studies, one correlational and two experimental, we investigated the relationship between (plastic) litter and restoration after a walk. In Study 1, participants did a self-selected restorative walk and afterwards reported observed litter. In two experimental studies, we manipulated the presence of plastic waste, biowaste (which served as an active control condition with human-sourced but degradable litter), and no waste in a virtual (i.e., video; Study 2) and an imagined (Study 3) forest walk. In all studies, we assessed subjective restoration, current affect and connectedness to nature, attractiveness and preference of scenery, as well as plastic-related problem awareness, intentions, and policy support. Results showed that litter, especially from plastic, is associated with harmful changes in subjective restoration, affect, and the perception of the scenery. Connectedness to nature, as well as plastic-related problem awareness, intentions, and policy support were not affected by the presence of plastic. Thus, plastic pollution influences human wellbeing negatively, but did not affect factors important to reduce consumption. Therefore, more research on tackling the plastic crisis is needed.