Following the latest round of expansion, the BRICS countries have formally entered the era of “Greater BRICS” cooperation. Maritime security governance collaboration constitutes a vital component of this enhanced security partnership, providing robust support for the stable advancement of maritime economic cooperation. Maritime security governance cooperation among the “Greater BRICS” countries is imperative, driven by the urgency of maritime security issues, the unique advantages of the BRICS cooperation mechanism, and new opportunities arising from the expanded membership. Simultaneously, such cooperation possesses considerable feasibility, grounded in both shared understanding and practical foundations. Currently, the progress of maritime security governance cooperation among the “Greater BRICS” countries is slow, facing challenges such as a weak foundation of shared interests, relatively lagging agenda setting, mechanisms that require refinement, and a complex and volatile external environment. In response, the “Greater BRICS”countries should jointly build a community of shared interests in maritime security governance cooperation, establish efficient cooperation mechanisms, highlight key areas of cooperation, and promote the establishment of a new order for global maritime security governance cooperation. As a founding member and the largest developing country, China should clearly define its role in the maritime security governance cooperation among the “Greater BRICS”countries as a leader in agenda setting, a promoter of strategic alignment, a provider of public goods, an enhancer of efficient mechanisms, and a coordinator of divergent interests. This will facilitate the smooth advancement of maritime security governance cooperation.