Seawater electrolysis is emerging as a promising method for sustainable hydrogen production, utilizing the vast resources of the ocean. The article discusses the advantages of direct seawater electrolysis, highlighting its potential to address the challenges associated with traditional methods. Several demonstration projects, including the Energy Observer vessel from Toyota and the Sealhyf platform, demonstrate the feasibility of generating hydrogen from seawater electrolysis. However, challenges such as seawater impurities and low ionic conductivity need to be overcome for efficient electrolysis. Researchers have developed various strategies to enhance electrolysis efficiency, such as catalyst engineering and membrane-based approaches. Innovative catalyst designs have shown promising results in laboratory settings, aiming to optimize hydrogen production in seawater environments. The article emphasizes the importance of direct seawater electrolysis, which eliminates the need for additional purification steps, making it a cost-effective solution for large-scale hydrogen generation. One notable development is the proposal of a water phase-transition migration mechanism for seawater electrolysis, which has demonstrated long-term stable operation in Shenzhen Bay with low energy consumption. This strategy offers a scalable and efficient approach to direct seawater electrolysis, resembling fresh water splitting. The article also highlights the need for further research on fluctuating wave conditions to validate the practical application of direct seawater electrolysis in marine environments.