A cause of losses in energy and carbon conversion efficiencies during the electrochemical CO₂ reduction reaction (eCO₂RR) can be attributed to the formation of carbonates (CO₃^2–), which is generally considered to be an electrochemically inert species. Herein, using in situ Raman spectroscopy, liquid chromatography, ¹H nuclear magnetic resonance spectroscopy, ¹³C and deuterium isotope labeling, and density functional theory simulations, we show that carbonate intermediates are adsorbed on a copper electrode during eCO₂RR in KHCO₃ electrolyte from 0.2 to −1.0 V_RHE. These intermediates can be reduced to formate at −0.4 V_RHE and more negative potentials. This finding is supported by our observation of formate from the reduction of Cu₂(CO₃)(OH)₂. Pulse electrolysis on a copper electrode immersed in a N₂-purged K₂CO₃ electrolyte was also performed. We found that the carbonate anions therein could be first adsorbed at −0.05 V_RHE and then directly reduced to formate at −0.5 V_RHE (overpotential of 0.28 V) with a Faradaic efficiency of 0.61%. The nature of the active sites generating the adsorbed carbonate species and the mechanism for the pulse-enabled reduction of carbonate to formate were elucidated. Our findings reveal how carbonates are directly reduced to a high-value product such as formate and open a potential pathway to mitigate carbonate formation during eCO₂RR.