Campeche, the capital of Campeche State and a UNESCO World Heritage Site since 1999, participated in the GEF-6 Global Platform for Sustainable Cities (GPSC) through the Sustainable Cities Integrated Approach Pilot (SCIAP). Located along the Gulf of Mexico, Campeche combines rich colonial heritage with complex environmental challenges related to flooding, wastewater management, and coastal pollution. Rapid urban expansion and an aging water network have strained infrastructure and increased contamination risks to the local aquifer and the Campeche Bay. The SCIAP project focuses on cleaning up the bay and improving the city’s water and sanitation systems while enhancing local capacity for integrated urban planning. Supported by the GPSC, Campeche is advancing policies that balance heritage preservation, environmental protection, and sustainable coastal development—serving as a model for medium-sized cities addressing climate and water management challenges.