Sasthamkotta Lake eco-region is a freshwater Ramsar site in Kerala, India. Eco-regions are ecologically and geographically defined larger land or water mass areas with a characteristic assemblage of the ecosystem and significant biodiversity. A decentralized and locally self-sustaining mechanism has been achieved in managing this eco-region by a participatory model through a joint Biodiversity Management Committee (jBMC) constitution. BMCs are custodians of the environment, and biodiversity, confined to a village/Panchayat, as per Convention on Biological Diversity (CBD) guidelines and the Indian Biodiversity Act. This jBMC constitutes a network of statutory biodiversity experts from the BMCs of three Local Self Governments (LSGs) or Panchayath administrations, where the Sasthamkotta Lake is located. It has been formed to develop strategies to manage and conserve the freshwater lake and its biodiversity. The management action plan proposed by the jBMC for the Sasthamkotta Ramsar site includes systematic and continuous assessment of the current biodiversity status, identifying and mitigating threats, appropriate use of its resources for eco-restoration and better administrative programs for biodiversity enhancement. Our case study shows that the conservation model of a Ramsar site Eco-region is successful and could be replicated in other damaged natural ecosystems which need attention, for a sustainable future.