<p> Climate change has the potential to expose sea turtle nests to higher temperatures, which may negatively impact sea turtle hatchling vigor. In this study, loggerhead and green hatchlings were sampled from the Boca Raton, Florida beach and via lab incubation, and hatchling vigor was determined. Elevated nest temperatures decreased loggerhead and green turtle hatchling performance and corticosterone levels, with the most significant effects found in hatchlings exposed to maximum incubation temperatures above 35 &deg;C during late development. Lab-incubated loggerhead post-hatchling corticosterone levels and growth rates were also determined. The differences seen in corticosterone levels with overall nest incubation temperatures, mean temperatures during early, middle or late stages of development, and its negative correlation with hatchling performance improves our understanding of the underlying physiological mechanisms linking elevated incubation temperatures and sub-lethal physiological effects that may significantly impact hatchling survival, a critical step for sea turtle conservation in south Florida and elsewhere.</p><p>