Small wetlands remain underappreciated emission sources in the global methane budget. Using 30-m remote sensing data, we identify 160 million small wetlands (0.001–1 km²) in non-forested regions worldwide, contributing 24.1% of their total wetland methane emissions. Notably, methane emissions from small wetlands increased significantly (+9.9%) over 2003-2022, and very small (<0.1 km²) wetlands dominate the magnitude and growth of methane emissions. The repository contains codes of identifying small wetlands and estimating wetland methane emissions. Specifically, we used the GWL_FCS30 wetland dataset, and used ancillary datasets including HydroLAKES, SWOT PLD, Global River Width from Landsat, and Global Dam Watch Database, to exclude water bodies such as lakes, ponds, rivers, streams, and reservoirs.