Taiwan highly depends on food imports and has only limited arable land available as an island. Food production is projected to decrease due to climate change, while food demand is expected to increase on account of ongoing population growth. Current agriculture practices negatively affect the environment and human health, mainly by utilizing fossil fuels, chemical fertilizers, and pesticides. Hence, the development and optimization of innovative agriculture are necessary to address the adverse effects of conventional food production systems, such as nutrient pollution, to improve sustainability. Aquaponics, the combination of hydroponics and aquaculture, potentially serves as a sustainable food production method. It has become increasingly popular in recent years, as aquaponics can have a lower environmental impact than other agriculture types. Therefore, exploring the environmental impact of local aquaponic systems can contribute to food security in Taiwan. In this regard, the current study used the life cycle assessment (LCA) tool to evaluate the environmental impact of the production of fish and lettuce in an aquaponic farm in Yilan, Taiwan. From a cradle-to-farmgate perspective, two functional units, 1 kg fish and 1 kg lettuce, were investigated. The results were compared with literature studies on traditional agriculture, hydroponics, aeroponics, and aquaculture. The LCA found that aquaponics had a higher impact in almost all categories regarding lettuce production and performed comparably to other aquaculture systems, except for showcasing higher GWP and CED. However, the analysis of environmental sustainability scenarios suggested that the environmental impact could be significantly reduced for both functional units, respectively. As shown in this study, potential reductions could be achieved by replacing fertilizer with aquaponic sludge (−23 % FWE), introducing Black Soldier Fly larvae as fish feed (−11 % MWE, −14 % LU, and − 5 % WC), and integrating a solar power system (−70 % GWP, −35 % TA & FWE, and − 16 % MWE) on the greenhouse rooftop. By implementing these sustainability measures, fish production in aquaponics would outperform most aquaculture systems considered. Therefore, aquaponics represents a promising sustainable alternative to other aquaculture systems, thus potentially contributing to Taiwan's food security. • Taiwan is increasingly facing the problem of food insecurity. • Aquaponics represents an environmentally friendly alternative for local production. • LCA highlights the potential of aquaponics in particular for fish farming. • Cooling, energy, and feed are major environmental challenges of aquaponic systems. • Solar power systems can decrease the environmental impact of aquaponics. [ABSTRACT FROM AUTHOR]