Negative emissions technologies (NETs), which result in the removal of CO 2 from the atmosphere, will be necessary to limit global warming to 2 °C. Unlike point-source CO 2 capture, NETs are agnostic to the emission source, and reduce the existing atmospheric CO 2 concentration. This enables NETs to address distributed emissions from transportation and past emissions that have led to existing atmospheric CO 2 concentrations. Despite their critical necessity, there are relatively few NETs that have been developed, and existing technologies do not have sufficiently detailed techno-economic analyses to allow comparison for the purpose of strategic investment and policy decisions. An analysis was performed of the economic feasibility of a novel platform of candidate NETs – indirect ocean capture (IOC) – through industry-validated economic and chemical process modeling supported by inputs from a prototype system. This manuscript details the development of a high-fidelity estimate of the cost of avoided CO 2 emissions from this NET by coupling scaled experiments to economic analyses. For the lowest-cost scenario of co-location with a desalination plant, a likely cost of $604 per metric ton of avoided CO 2 (tCO 2 ) was found, and a best-case cost of $373/tCO 2 . Through improvements to unit processes, creative process optimization, and reduced carbon-neutral electricity prices, the cost of IOC negative emissions may be reduced in the future. Although NETs won’t likely require deployment for several years in order to limit warming to 2 °C, an objective techno-economic assessment of the options on the table will ensure that the best technology is developed and ready when deployment is required.