Aerial surveys of marine waters up to 222 km from shore in the Gulf of Mexico and nearby Atlantic Ocean suggest that marine turtles are largely distributed in waters less than 100 m in depth. The loggerhead turtle (Caretta caretta) was observed nearly 50 times as often in waters off eastern and western Florida as in the western Gulf of Mexico. Loggerheads were present year round but the frequency of sightings in the winter months was lower than at other seasons. Green turtles (Chelonia rnydas) were infrequently observed but were most conspicuous in waters off eastern Florida. Kemp's ridleys (Lepidochelys kempi) were most frequently sighted off southwestern Florida and rarely observed in the western Gulf of Mexico. Leatherback turtles (Dermochelys coriacea) were more conspicuous on the continental shelf than in adjacent deeper waters. A concentration of leatherback and loggerhead turtles occurred west of the Gulf Stream Current in August 1980, near Brevard County, Florida.