Regions of China have generated large CO2 emissions, and investigating the means for reducing them has become a priority. The geological storage of CO2 is one technique gaining interest, and the offshore Bohai Basin is believed to be a promising option to aid emissions mitigation. The Cenozoic sedimentary rocks, which measure more than 10,000 m in thickness and have diverse depositional systems and good reservoir-seal assemblages, appear to offer the most favorable circumstance for CO2 storage in the offshore Bohai Basin. The Minghuazhen Formation of the Pliocene–Miocene consists of thick and extensive mudstone, especially its lower member, and is regarded as an excellent regional seal cover. The Miocene sandstone, including the lower member of the Minghuazhen Formation and the Guantao Formation, has high porosity and permeability and is a preferred target storage reservoir. The Dongying Formation and the Shahejie Formation of the Oligocene–Eocene are also storage options. Based on the pore volume method suggested by the U.S. Department of Energy, we calculated the effective storage capacity of the Cenozoic sedimentary rocks in the offshore Bohai Basin. The mean storage capacity is approximately 192 Gt, representing a huge capacity on a par with that of the Pearl River Mouth Basin, and potentially offering storage capacity for hundreds of years of CO2 emissions from the Circum-Bohai-Sea region. Considering the storage capacity and risk, the Bozhong Sag area may offer the most promising early CO2 storage option in the basin.