Established in 1975, the Royal Commission for Jubail and Yanbu (RCJY) has played a pivotal role in developing two major coastal industrial centers in Saudi Arabia: Jubail on the Arabian Gulf and Yanbu on the Red Sea. These cities have evolved from undeveloped coastal zones into sophisticated industrial complexes that support the Kingdom’s efforts to diversify its economy away from oil dependence, in alignment with Vision 2030 objectives. This study presents a comprehensive comparative assessment across multiple domains, including industrial categorization and expansion, investment trends, infrastructure capacity, agricultural and fisheries output, population characteristics, corporate social responsibility programs, port operations, and international positioning. Evidence from RCJY publications, national statistics, and scholarly sources indicates that Jubail substantially exceeds Yanbu in terms of scale, investment volume, industrial concentration, and infrastructural development. Jubail contributes 85% of Saudi Arabia’s non-oil exports, 11.5% of national GDP, and 7% of worldwide petrochemical production, while capturing more than half of the Kingdom’s inbound foreign direct investment. Although Yanbu operates on a smaller scale across most indicators, it shows promising development in areas such as green hydrogen production and environmentally sustainable industrialization. The analysis identifies significant developmental imbalances, including an investment difference of approximately 440 billion SAR, a population disparity of around 330,000 residents, and an area variance of 410 km². These gaps highlight the importance of implementing focused policy measures to foster equitable regional advancement. The study concludes with data-supported policy suggestions in five key areas: foreign investment incentives, infrastructure enhancement, industrial diversification, workforce skill development, and environmental sustainability integration, all aimed at achieving balanced progress consistent with Vision 2030 goals.