This study examines the legal and economic barriers to synchronizing the regimes of Special Economic Zones (SEZs) in BRICS countries and proposes mechanisms for their harmonization to strengthen trade and investment cooperation. A comparative analysis of SEZ models (China’s “special zones”, Russia’s Priority Development Areas (PDAs), and India’s SEZs) reveals key differences in tax, customs, and environmental requirements. Using econometric modeling (2015–2024) and SWOT analysis, the study demonstrates that unifying 30% of SEZ parameters could increase intra-BRICS investment flows by 15%–20% by 2030. The practical contribution lies in the proposed model of “SEZ hubs”—clusters connecting zones from different countries around strategic industries (digital technologies, pharmaceuticals). The findings can inform the optimization of BRICS agreements and help reduce transaction costs for firms.