The coastline of southwestern Hudson Bay and western James Bay (HBJB) provides crucial habitat for thousands of birds, fish and mammals, and is the homeland of the Omushkego Cree. With increasing development within the HBJB Lowlands, compounding the effects of climate change, Omushkego Cree are leading conservation initiatives in their traditional territory and the adjacent marine region. The main objective is to protect the peatlands of HBJB Lowlands and understand changes to the natural processes that contribute to carbon storage. Understanding the carbon system along the aquatic continuum from the land, to rivers, to sea, is crucial for understanding the full impacts of climate change and anthropogenic disturbance on the coastal ecosystems, and to better integrate knowledge on the region’s carbon cycle into Canada’s carbon accounting. The work being conducted seeks to quantify delivery of nutrients and terrestrial-derived carbon in its different forms via rivers to the coast and consider impacts on coastal ecosystems from factors such as warming, ocean acidification and sedimentation. In 2023, community-partnered river and coastal monitoring programs were initiated with Moose Cree First Nation and Weenusk First Nation to study the Moose River and Winisk River watersheds and associated coasts. In 2024, in partnership with Parks Canada, study sites were added in Wapusk National Park (Broad and Owl Rivers), at the northern boundary of the HBJB Lowlands. Here, we present preliminary results and discuss next steps in our partnered research, with the aim of addressing both global research questions and local monitoring objectives and research priorities.