The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to .2000 g dry m22) and annual foliar productivity of the dominant seagrass T. testudinum (,200 and .2000 g dry m22) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes . 16uN. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ,1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea- urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration.