AbstractMethane (CH₄) is a potent greenhouse gas with a warming potential 84 times that of carbon dioxide (CO₂) over a 20‐year period. Atmospheric CH₄ concentrations have been rising since the nineteenth century but the cause of large increases post‐2007 is disputed. Tropical wetlands are thought to account for ∼20% of global CH₄ emissions, but African tropical wetlands are understudied and their contribution is uncertain. In this work, we use the first airborne measurements of CH₄ sampled over three wetland areas in Zambia to derive emission fluxes. Three independent approaches to flux quantification from airborne measurements were used: Airborne mass balance, airborne eddy‐covariance, and an atmospheric inversion. Measured emissions (ranging from 5 to 28 mg m⁻² hr⁻¹) were found to be an order of magnitude greater than those simulated by land surface models (ranging from 0.6 to 3.9 mg m⁻² hr⁻¹), suggesting much greater emissions from tropical wetlands than currently accounted for. The prevalence of such underestimated CH₄ sources may necessitate additional reductions in anthropogenic greenhouse gas emissions to keep global warming below a threshold of 2°C above preindustrial levels.