There is no existing research documenting the influence of temperature in tropical island climates. This knowledge gap prevents us from understanding how to effectively address the impacts of temperature in France’s overseas departments and regions (DROMs). Against the backdrop of rapid climate change, this study aims to establish the influence of temperature on mortality in the DOMs, in order to determine short- and medium-term prevention and adaptation needs. A study area was defined for French Guiana, mainland Guadeloupe, Martinique, Réunion, and Mayotte. A similar protocol for modeling the temperature-mortality relationship was applied in each area (with the exception of Mayotte, where the lack of consolidated mortality data prior to 2014 prevented the analysis from being finalized), and the results were then combined in a meta-analysis. The general shape of the temperature-mortality relationship and the orders of magnitude of the calculated relative risks (RR) are consistent with those observed in other regions of the world. They confirm that temperature influences mortality and that the risk of death increases rapidly as temperatures approach the most extreme values. The cumulative RR over 0–10 days following exposure to a temperature at the 99th percentile of the temperature distribution is 1.20 [95% confidence interval (CI) 1.06–1.42] (meta-analysis, RR relative to the 50th percentile). Nearly 5% of total mortality is attributable to suboptimal temperatures, primarily representing a heat-related effect. These results support the implementation of measures to mitigate the impacts of temperature, particularly heat, in the French overseas departments and territories (DROM), and the integration of this health risk into climate change adaptation policies.