Despite great advances in the understanding of marine turtle biology over the past 60 yrs, there is still a paucity of demographic data on the juvenile stage of their life history. These data are required to adequately predict population trends for these long-lived marine turtle species. In the early 1990s, juvenile green turtles (Chelonia mydas) were observed in the Trident Turning Basin at Port Canaveral, Brevard County, Florida. We began a study in 1993 to assess the species composition, size class distribution, and degree of residency of the marine turtles utilizing this man-made embayment as developmental habitat. The results of the first 18 yrs of that study are related here. Juvenile green turtles constituted 99.4% of the marine turtle captures. Straight carapace lengths (SCL) of turtles ranged from 20.0 to 52.0 cm with a mean of 31.7 cm, smaller than those observed in other known green turtle developmental habitats in Florida. The mean SCL of the green turtles in the basin has declined over the course of the study. Although initially there was a high recapture rate of turtles tagged in the basin, that rate declined significantly along with the size of the turtles at their most recent recapture and the interval of time between their first capture and most recent recapture. We attribute these declines to the increase in the number of juvenile green turtles recruiting to developmental habitats along Florida's east coast and to the limited forage available in the basin. Population surveys over the past 13 yrs of the study yielded estimates that ranged from 27 to 224 green turtles in the basin, with a mean estimate of 61 ± 10 turtles. The results of this study illustrate the value of long-term monitoring projects in understanding both juvenile green turtle habitat preferences and sea turtle population dynamics.