Understanding the intrinsic properties of the hydrated carbon dioxide radical anions CO2.-(H2O)n is relevant for electrochemical carbon dioxide functionalization. CO2.-(H2O)n (n=2-61) is investigated by using infrared action spectroscopy in the 1150-2220 cm-1 region in an ICR (ion cyclotron resonance) cell cooled to T=80 K. The spectra show an absorption band around 1280 cm-1, which is assigned to the symmetric C-O stretching vibration νs. It blueshifts with increasing cluster size, reaching the bulk value, within the experimental linewidth, for n=20. The antisymmetric C-O vibration νas is strongly coupled with the water bending mode ν2, causing a broad feature at approximately 1650 cm-1. For larger clusters, an additional broad and weak band appears above 1900 cm-1 similar to bulk water, which is assigned to a combination band of water bending and libration modes. Quantum chemical calculations provide insight into the interaction of CO2.- with the hydrogen‐bonding network.