Saltmarshes can be both sinks and sources of the greenhouse gases (GHGs) methane and nitrous oxide. Populations of invasive Phragmites australis have displaced native saltmarsh vegetation across much of Eastern Canada, including along the Quebec coastline of the Restigouche Estuary. Research on the impact of the invasive reed Phragmites australis on saltmarsh GHG fluxes has been limited, with no reports in Canadian marshes. Previous GHG research on invasive Phragmites has been limited to more southern latitudes on the Northwest Atlantic coast and occurred almost exclusively during the growing season. In this presentation, we report on the fluxes of GHGs from an invaded saltmarsh on the southern shore of Gespe’gewa’gi along the Restigouche Estuary during spring, summer, fall, and winter sample events. To measure GHG fluxes, we used a modular, dark static chamber tall enough to accommodate the ~3 m height of Phragmites without damaging its stems, avoiding a common pathway for error in gas sampling. The Phragmites stands were a source of methane during each sample event and peaked in our winter sampling event. In contrast, the stands were often a sink for nitrous oxide, particularly during the spring. We believe that our measurements are the first taken from Phragmites stands at higher latitudes with frozen soil. The results presented here emphasize the need for sampling outside the growing season and provide a novel insight on the impact of invasive Phragmites saltmarshes of Eastern Canada.