Chelonia mydas (Green Turtle) foraging areas, where juveniles, subadults, and adults of diverse natal origins coalesce and spend a large portion of their lives, can be located thousands of kilometers from nesting beaches. Unfortunately, the natal origin of turtles in many foraging areas remains unknown. Resolution of this issue was recently listed among the conservation priorities for the species by a global panel of Green Turtle researchers. We examined the genetic diversity and natal origins of Green Turtles from a well-known foraging area in the western Gulf of Mexico. Bayesian mixed-stock analysis of mitochondrial DNA haplotypes was used to demonstrate that an overwhelming percentage (∼95%) of individuals in the western Gulf of Mexico foraging group likely originate in other Gulf of Mexico and northern Caribbean rookeries, with smaller contributions from the western and southern Caribbean, and potentially the Mediterranean Sea. Management of Green Turtles in the western Gulf of Mexico will be improved by linking conservation efforts aimed at this foraging group to turtle aggregates occurring in other critical habitats within the recently defined northwest Atlantic Green Turtle regional management unit.