Understanding the long-term variabilities and trends of global oceanic surface wind speed is critical for extracting wind power. Therefore, 84 years (from 1940 to 2023) of global 10-m wind speed data derived from the fifth-generation ECMWF reanalysis, ERA5 (European Centre for Medium-Range Weather Forecasts Reanalysis v5), were utilised to analyse the long-term trends in the global 10-m wind speed. The results revealed that the wind speeds at the oceanic surface are much greater than those at the terrestrial surface, causing marine areas to be more suitable for extracting wind power. The global average 10-m oceanic wind (OW) speed increased by 0.074 % annually, while 0.065 % and 0.082 % were found for the Northern Hemisphere (NH) and Southern Hemisphere (SH), respectively. The region with the most critical trend of increasing 10-m OW speed is in the SH at S60°, with an average annual increase of approximately 0.02 ms