Nightly movements of bats have been described for only a handful of species around the world. The lesser long-nosed bat (Leptonycteris yerbabuenae) is a migratory pollinator recently delisted from threatened status in Mexico and proposed in early 2017 to be delisted from endangered status in the United States. Documenting the nightly movements of these bats and how they use the desert ecosystem when they spend the summer in Sonora, Mexico, is critical for protection of their habitat and to understand food availability and landscape use. We used inert fluorescent powder to mark thousands of bats emerging from a cave used as a day roost, then examined bats captured at known foraging sites for this marker. We also marked individuals captured at foraging sites with different colors of powder that enabled us to search for dyed feces in the cave. Our results demonstrate that these bats made round trips of ca. 100 km flying from their roost cave to their nightly foraging grounds, which exceeds all distances known from other phyllostomid or nectar-feeding bats in the world.