ABSTRACT. Courtship and mating behavior are important life cycle aspects of marine turtles not easily observed by researchers. A pair of loggerhead sea turtles (Caretta caretta) was documented circling, attempting and successfully mounting in the Gulf of Ulloa, Mexico. This type of activity is part of an already described courtship and mating behavior for other sea turtle species; however, this is the first report of open-ocean courtship and mating behavior by loggerheads in the Northern Mexican Pacific Ocean.