Caves are among the most used and important roosts for hundreds of bat species worldwide. However, caves remain some of the least known and most threatened environments globally. Documenting the richness of bat species in caves is important not only to draw attention to the uniqueness and relevance of these roosts, but it also contributes to the identification of priority sites for the conservation of bats and the cave fauna dependent upon them. Here, we assessed and described an exceptionally high bat richness in a group of caves in southeastern Tocantins, central Brazil. Inventories carried out in 19 caves resulted in seven families and 31 bat species, of which three were new regional records. Twelve caves were used by threatened and endangered bat species, eight had high diversity indices, and seven caves had high species richness, including one cave that may hold a world record with 26 bat species found inside. The variation in beta diversity is mainly due to species turnover, which indicates that protecting the largest possible number of caves would be ideal for the most efficient conservation of local bat assemblages. The sampled region stands out for its high potential for the conservation of endangered species, and we strongly recommend the full protection of 15 caves classified as a priority for conservation.