<p>Freshwater ecosystem services in peri-urban catchments are increasingly threatened by land-use intensification, infrastructure deficiencies, and climate variability, with significant implications for environmental management and community well-being. This study examines ecosystem services in the Kat River Catchment, Eastern Cape, South Africa, using a multidimensional participatory mapping approach to assess service types, perceived importance, perceived spatial and temporal changes in availability and quality. A total of 54 stakeholders, representing communities within the catchment (the Kat River Catchment Forum), commercial farmers, subsistence farmers, and non-farming households participated in this study. There were 23 participants in a participatory mapping workshop and 31 semi-structured interview respondents. Provisioning services such as water, reeds, wood, sand, fish, and medicinal plants were consistently rated as highly important to local livelihoods, while cultural services including spiritual and recreational uses were rated as moderately important. Most ecosystem services were perceived to have deteriorated since the year 2000, particularly water quality and availability, reeds used for craft production, and fish for food and recreation. Participants attributed these declines to climate variability, agricultural intensification, failing wastewater treatment infrastructure, and inadequate solid waste management. The findings demonstrate how participatory approaches can generate locally grounded evidence of ecosystem service degradation and identify governance and infrastructure gaps. Integrating local ecological knowledge into catchment management, strengthening wastewater treatment performance, and improving pollution control are critical for enhancing ecosystem service sustainability and supporting adaptive environmental management in peri-urban river systems.</p><p></p>