While there are reportedly 15 turtles in the Okefenokee Swamp, my most commonly photographed species has been the Coastal Plain Cooter (Pseudemys concinna ssp. floridana). While abundant in the Okefenokee Swamp, they are found all along the coastal plain (hence the common name) from southeastern Virginia, south into Florida, and west into Alabama.
They can be quite large (up to a 13-inch carapace length) and would be quite conspicuous if they didn’t dive off their basking spots long before your canoe approaches. As we paddle along, if I keep my binoculars trained ahead, I typically see these cooters sliding into the water left and right all along the Okefenokee canoe trails. On our springtime Okefenokee trips, one or two will occasionally remain out in the warm sun long enough for a closer photograph being reluctant to dive back into the cool water.
iNaturalist observation: https://www.inaturalist.org/observations/45352341