As 41 % of China’s CO₂ emission comes from coastal provinces and cities, permanent sequestration of anthropogenic CO₂ in offshore sediments is a priority to achieve China’s national goal of net zero by 2060. In this paper we evaluate the potential of CO₂ sequestration in the major oil and gas reservoirs in the northern South China Sea (NSCS) bordering the southern provinces of Guangdong, Guangxi and Hainan. The calculation of the CO₂ storage potential is based on voidage replacement for individual oil and gas fields. Our study shows that the overall CO₂ storage potential in oil and gas reservoirs in the four major geological basins in NSCS has low, mid and high value of 1015.8, 1082.7 and 1151.5 Mt, respectively. About 84 % of the storage potential resides in gas reservoirs and 16 % in oil reservoirs. Though this storage volume is modest, it is adequate for an industry scale CO₂ storage demonstration project where one to several Mtpa CO₂ can be injected. Furthermore, we have identified two relatively mature gas fields, Dongfang 1-1 and Yacheng 13-1 in the Yinggehai basin as potential candidates for such a demonstration project where industrial CO₂ from Hainan Island can be sequestered permanently. A feasibility study on this is warranted.