This workshop was held August 21-23, 2018 at the USGS Woods Hole Coastal and Marine Science Center, and brought together 28 researchers from 15 institutions to refine conceptual models of tidal exchange in coastal wetlands, with focus on dissolved organic and inorganic carbon, particulate carbon, and sediment. The group engaged in discussion of concentration and water flux measurement methods and frequency, instrumentation challenges in estuarine and salt marsh deployment, and modeling approaches to refine carbon flux measurements. In addition, they are working on continental-scale lateral flux estimates for the United States, an important term in the coastal carbon budget. Discussions highlighted the poor state of knowledge regarding this flux and its drivers, and the need for extended time-series of high-frequency measurements to capture variability in flux rates in these dynamic ecosystems. The continental U.S. flux estimation, and other related products are intended to be published in an AGU special collection on the U.S. coastal carbon cycle, including the journal Global Biogeochemical Cycles. The collection is open to submissions from anyone. Look for a session at the upcoming Coastal & Estuarine Research Federation (CERF) meeting related to this workshop. Learn more about this workshop and working group on their web page.