The aim of this report card is to provide a transparent, timely, and geographically detailed assessment of 2010 Coastal Bays health. Coastal Bays health is defined as the progress of four water quality indicators (TN, TP, Chl a, DO) and two biotic indicators (seagrass, hard clams) toward scientifically derived ecological thresholds or goals. The six indicators are combined into one overarching Coastal Bays Health Index, which is presented as the report card score. Detailed methods are available at www.eco-check.org/reportcard/mcb/2010/. The overall score for the Coastal Bays was a C in 2010. All regions declined in overall health when compared to 2009.