With challenges such as land availability and regulatory constraints, offshore renewable energy sector is poised to play a pivotal role in the transition to a low-carbon future. Among offshore technologies, wind and solar photovoltaic (PV) have emerged as the most promising solutions. However, a global assessment of offshore resources, particularly solar PV, remains lacking. Hence, we identify suitable areas for offshore wind and solar PV development on the basis of economic feasibility, technical constraints, and environmental considerations and quantify the national potential for electricity production and CO 2 reduction contributions. With a conservative assumption of using 1% of suitable areas, offshore wind and solar PV could generate ~6049 and 14,173 terawatt-hours of electricity annually. This would cover nearly 30% of the expected global electricity demand in 2050. The resulting reductions in carbon dioxide emissions could exceed 9 billion tonnes annually. These findings highlight the critical role offshore renewable energy can play in achieving a low-carbon future.