We combined three separate sequential annual data sets (2008–2010) to document general phenology of nesting seasons, reproductive frequency, and interclutch intervals (ICIs) of female Pseudemys texana (Texas River Cooter) and Trachemys scripta (Red-eared Sliders) occupying a spring system in Hays, County, Texas. Detection of gravid females was done through frequent monitoring of nesting areas over three entire nesting seasons. Of the 108 Pseudemys texana that nested in the first year, 54 (50%) also nested in two subsequent years. Of the 65 Trachemys scripta that nested in the first year, only 13 (20%) nested in all three years. Percent of females that nested only in the first year was 10% and 19% for P. texana and T. scripta, respectively. Individuals that nested only once in a season, did so over all days in a season. Multiple clutching within a season was observed for both species. Within year ICIs of females was approximately 30 days for both species and only about 30% of both species nested.