After a dramatic decline in the annual malaria incidence in Thailand since 2000, the Thai government developed a National Malaria Elimination Strategy (NMES) to end local malaria transmission by 2024. This study examines the expected costs and benefits of funding the NMES (elimination scenario) versus not funding malaria elimination programming (resurgence scenario) from 2017 to 2036. Two case projection approaches were used to measure the number of malaria cases over the study period, combined with a set of Thailand-specific economic assumptions, to evaluate the cost of a malaria case and to quantify the cost-benefit ratio of elimination. Model A projects cases based on national historical case data using a log-normal regression and change-point analysis model. Model B projects cases based on periodic Yala Province-level outbreak cycles and incorporating NMES political and programmatic goals. In the base case, both models predict that elimination would prevent 1.86-3.11 million malaria cases from 2017 to 2036, with full NMES implementation proving to be cost-saving in all models, perspectives, and scenarios, except for the health system-only perspective in the Model A base case and all perspectives in the Model A worst case. From the societal perspective, every 1 US dollars (US$) spent on the NMES would-depending on case projections used-potentially result in a considerable return on investment, ranging from US$ 2 to US$ 15. Although the two case projection approaches resulted in different cost-benefit ratios, both models showed cost savings and suggest that ending local malaria transmission in Thailand would yield a positive return on investment.