We investigated the relative contributions of various factors that influence seasonal changes in sea surface partial pressure of CO₂ (pCO₂, calculated from the measured pH and total alkalinity) in four regions of northwestern Greenland: Nares Strait, Lincoln Sea, Sherard Osborn and Petermann fjords. Using the temperature minimum layer as a proxy for winter conditions, we examined pCO₂ dynamics from the onset of sea-ice melt to summer. Our findings revealed significant spatial variability in pCO₂, driven by differences in temperature, freshwater inputs, and biological activity. In particular, in Sherard Osborn Fjord substantial freshwater inputs and strong stratification were found to enhance pCO₂ accumulation, while in Petermann Fjord biological CO₂ uptake was the main driver. This study, conducted in summer 2019, underscores the critical role of northwest Greenland’s coastal waters as a summer CO₂ sink. It highlights the complex interplay of physical and biogeochemical processes in modulating pCO₂, suggesting significant regional differences in CO₂ dynamics between two neighboring fjords.