Introduction: Reptiles are often overlooked when planning for conservation, as they are typically perceived as a persistent or tolerant group. Nonetheless, recent studies have shown their vulnerability. Identifying priority areas is crucial, and spatial prioritization is an essential analysis to optimize the scarce available resources for conservation. Furthermore, it is of the utmost importance to establish protected area networks that would keep their usefulness in the future, especially considering the enormous environmental changes that are currently occurring. Objectives: To evaluate the performance of the current protected area network (PA) and to identify potential areas for expansion, considering their persistence in time. Methods: We estimated species distributions for 177 reptiles on the Sierra Madre del Sur in Southeastern Mexico. The species were weighed according to their international conservation status, and future land use scenarios were incorporated to identify priority areas with Zonation software. Results: We found coincidences between priority areas for reptiles and zones previously identified for other groups. However, most regions with top priority rankings remain unprotected, considering the current established PA. Federal PA protects the highest percentage of priority areas, followed by areas voluntarily dedicated to conservation and state PA. We emphasize conserving natural land uses since they are the only ones that constitute the highest priority zones for reptiles. Conclusions: Our prioritization for reptile conservation entails efficient outcomes in terms of temporal permanence, amount of area to be protected, and coverage of species distribution, especially for small percentages of expansions to the current network of PA, making it an affordable proposal for implementation. Nonetheless, it is crucial to recognize that it is also important to consider social factors, possible conflicts of interest, and to evaluate the effectiveness of PA over time.