Herein, an efficient and facile approach to valuable β-hydroxy acid derivatives from readily available aryl epoxides and CO2 with high chemo- and regioselectivity under mild and sustainable electrochemical conditions is described. This approach showed broad substrate scope and good functional-group compatibility. In addition to aryl epoxides, four- to six-membered aryl cyclic ethers could all be tolerated in the reaction to provide synthetically useful hydroxy acids with high efficiency. Further late-stage carboxylation of complex molecules and drug derivatives demonstrated its potential application in the pharmaceutical industry. Mechanistic studies disclosed possible reaction pathways.