The COVID-19 pandemic accelerated global interest in wastewater-based epidemiology (WBE) as a complementary public health surveillance tool, capable of capturing both symptomatic and asymptomatic infections and providing earlier warnings than clinical testing in many contexts. While most established WBE programs originate from highly developed, well-resourced settings, far less is known about how WBE can be realistically developed, governed, and sustained in countries with fragmented sanitation networks and uneven laboratory capacity. Using the Philippines as a case study, this article synthesizes published studies, registered initiatives, institutional reports, and emerging government and utility-led programs to characterize an evolving national WBE landscape. Philippine pilots demonstrate feasibility for SARS-CoV-2 and antimicrobial resistance surveillance, while also revealing technical limitations related to detection sensitivity, environmental degradation of signals, and challenges posed by low sewerage coverage. Regional experience from the Association of Southeast Asian Nations countries indicates that wastewater and environmental surveillance can be operationalized even in mixed or informal sanitation environments, reinforcing the potential relevance of WBE in comparable settings. Building on these insights, this study outlines policy and research priorities, including transitioning from COVID-specific to multi-pathogen platforms, adopting sanitation-appropriate sampling strategies, investing in regional laboratory hubs and quality assurance, linking WBE outputs to decision-support systems, strengthening governance and data stewardship, addressing ethics and equity, and securing sustainable financing. Together, these considerations position WBE as a promising but still developing pillar of One Health surveillance in the Philippines and similar lower–middle-income contexts.