Dissolved organic matter (DOM) decomposition critically mediates carbon emissions from inland waters, which release disproportionately large amounts of CO2 into the atmosphere. Anthropogenic activities, including agricultural fertilizer runoff (causing eutrophication and algal blooms) and land-use changes (affecting water browning), are expected to increase both recalcitrant terrestrial and labile autochthonous DOM, potentially enhancing the decomposition of native DOM via labile carbon inputs (known as the priming effect, PE). However, current studies report negligible aquatic DOM PE. Here, employing 13C-tracing method specifically designed to track native DOM decomposition, we investigated the pattern and mechanisms of DOM PE across 30 waters (encompassing lakes/reservoirs, rivers, and wetlands) characterized by distinct nutrient levels, DOM composition, and microbial community structures. We found positive DOM PE in 70 % of the studied waters, with the mean decomposition rate of native DOM enhanced by 33 ± 8 % upon glucose amendment. Importantly, wetlands exhibited the strongest PE, owing to their high DOM aromaticity and unique microbial communities (particularly elevated abundances of Patescibacteria), which encode numerous glycoside hydrolases capable of degrading both labile and recalcitrant substrates. Our findings highlight primed decomposition of native DOM as a prevalent but underappreciated driver of carbon emissions in inland waters, suggesting that this process should be considered in efforts to predict inland water carbon dynamics under global change.