Basking is an understudied aspect of turtle biology, especially considering how frequent and observable it is in some species. Researchers have suggested many physiological roles that basking likely fulfills in turtles. We documented seasonal basking behavior of the yellow-blotched sawback (Graptemys flavimaculata) on the Leaf River, a tributary of the Pascagoula River in southeastern Mississippi. We used binoculars and a spotting scope to determine G. flavimaculata individual- and population-level basking patterns throughout the main active months (April–October) and across the daily activity period; we also describe a new method to determine population basking percentage that may be useful for future aquatic turtle surveys. We found distinct differences in individual- and population-level basking behavior across months, sexes, and the daily activity period. We also documented differences in basking structures used between the sexes but found little correlation between population-level basking and several environmental temperature variables.