Spring ecosystems play a crucial role in the global carbon budget, often exhibiting high CO₂ concentrations due to groundwater inputs enriched with CO2, e.g. via soil respiration and rock weathering. Despite their obvious importance, springs remain underrepresented in carbon cycle assessments, leading to an incomplete understanding of their role in regulating carbon fluxes at local, regional, and global scales. The magnitude of CO₂ concentrations in springs depends on several factors, including lithology, aquifer type, and hydrological connectivity. However, little research has quantified CO₂ fluxes from mountain springs and their variability. To address this knowledge gap, we conducted a year-long study of four alpine springs in the Adamello Brenta Nature Park (Italian Alps), sampled CO₂ concentrations across different seasons and modelled CO₂ fluxes and emissions to assess both spatial and temporal variability. Our findings reveal high CO₂ fluxes in some alpine springs and substantial heterogeneity among spring types, with geomorphic and geological characteristics playing a key role in shaping this variability. This suggests that alpine springs contribute significantly and in diverse ways to regional carbon budgets, with broader implications for carbon cycling in mountainous landscapes. We argue that mountain spring ecosystems should be recognized as hidden carbon hotspots, playing a crucial – yet often overlooked – role in carbon cycling. Springs conservation is essential for maintaining biodiversity and ecosystem stability, and for ensuring their role in global carbon regulation, as these ecosystems can influence carbon storage, sequestration, and fluxes across aquatic and terrestrial ecosystems.