While many different lithium carbonate production routes have been developed, existing life cycle assessments (LCA) of lithium carbonate production from brines are mainly based on a single brine operation site. Hence, current life cycle inventories do not capture the variability of brine sites and misestimate life cycle impacts. This study presents a systematic approach for LCA of existing and future lithium carbonate production from brines, which can furthermore be applied to geothermal brines or seawater. It has been used to model life cycle inventories of three existing and two upcoming brine operations in Argentina, Chile, and China, and is combined with regionalized life cycle impact assessment. Impacts on climate change, particulate matter human health impacts, and water scarcity from lithium carbonate production differ substantially among sites. Existing life cycle inventories for lithium-ion battery production underestimate climate change impacts by up to 19% compared to one from our study.