In recent years, biofluorescence has been observed in an increasing diversity of animals. Biofluorescence has been primarily examined in cnidarians, and it is also known to occur in other marine animal phyla, including Ctenophora, Annelida, Arthropoda, and Chordata. Most recently, the phenomenon has been shown to be phylogenetically widespread and phenotypically variable in cartilaginous and ray-finned fishes. Here we report on the first observation of fluorescence in a marine tetrapod, sea turtles.