Objective: Ultra-processed beverages (UPB) have known adverse impacts on health, but their impact on the environment is not well understood across different environmental indicators. This study aimed to quantify the environmental impacts of water-based UPB and bottled waters sold in Australia and assess the impacts of various scenarios which may reduce such impacts in the future. Design: This study presents a quantitative environmental impact assessment of a major sub-category of UPB (water-based UPB, including soft drinks, energy drinks, cordials and fruit drinks) and non-UPB (bottled waters) in Australia. Alternative mitigation scenarios based on existing health and environmental targets were also modelled using sales projections for 2027. Sales data from Euromonitor International were matched with environmental impact data from peer-reviewed lifecycle assessment databases. Environmental impact indicators included greenhouse gas emissions, land use, eutrophication potential, acidification potential, water scarcity and plastic use. Setting: The Australian beverage supply in 2022 and projected sales for 2027. Participants: N/A Results: Environmental impacts of UPB were higher than bottled waters. UPB accounted for 81–99 % of total environmental impacts, partly driven by the volume of sales. Reformulation, reducing UPB consumption and increasing recycling all led to meaningful reductions in environmental impacts but with diverse effects across different environmental indicators. The largest reductions occurred when policy scenarios were combined to represent a suite of policy actions which aimed to meet health and environmental targets (30–82 % environmental savings). Conclusions: The results indicate that implementing a suite of policies which act to target multiple drivers of environmental harm are likely to lead to the most environmental benefits.