Oil-dependent cities, emerging from the discovering and exploitation of non-renewable resources, exhibit distinct characteristics. Their growth and development are intrinsically linked to oil, fostering single-industry economies that once drove prosperity. As these resources deplete, these cities face periods of decline. Iranian cities like Masjid I Sulaiman, Agha Jari, Haftkel, Naft Safid are not exempt. As the oil industry wanes, they grapple with challenges in urban identity, economy, and socio-ecological balance. In contrast, despite limited reserves, Singapore has become a global oil and gas hub, ranking among the top ten cities for offshore drilling rig construction. This study employs a comparative approach to identify optimal strategies for post-oil sustainability in Iranian oil cities by examining internal and external factors influencing urban economic development. It proposes solutions to diversify economies and transition to sustainable futures based on Singapore’s success. The question arises: “What practical actions can oil-dependent cities implement to facilitate a smoother transition towards a sustainable future?” The research reveals that economic diversification, effective social policies, and reduced reliance on non-renewable resources are crucial. The potential for developing commercial and service sectors and leveraging historical assets for future-oriented and sustainable development represents key strengths. By combining internal and external factors, these cities can develop effective strategies to mitigate potential crises and capitalize on their strengths for long-term sustainability in a post-oil era.