The world's energy landscape is undergoing a significant transformation, driven by the urgent need to address the climate issues and growing sustainable energy demand. Hydrogen can be produced from renewable sources and may play a crucial role in the zero-carbon economy, which is regarded as a promising alternative to fossil fuels. Currently, hydrogen production via water electrolysis still relies on high-purity water, while seawater electrolysis benefits from the abundance of seawater, which can be particularly beneficial for water-scarce countries, and deep-sea applications, such as floating platforms or islands. However, it faces several challenges, such as impurities in seawater, the harsh marine environment, and unpredictable costs. Ongoing research and development efforts are focused on addressing these challenges through innovative solutions, including the design of robust electrocatalysts, the development of smart integrated structures, and the exploration of innovative coupled systems. In this review, the significant progress mentioned above aimed at improving the efficiency of seawater electrolysis is briefly discussed, and the challenges and prospects are provided.