Alpine waterscapes, found across every continent, are rich in diverse ecosystems, from fast-flowing streams to tranquil bogs, and home to a range of organisms, from microscopic life to large vertebrates. While species richness tends to be low at high altitudes, mountain regions often boast surprisingly high biodiversity on a larger scale. These aquatic environments are marked by a mix of widespread as well as highly specialized species, unique endemics, and hidden cryptic diversity. However, alpine waterscapes are undergoing significant transformation, driven by both global environmental shifts and local human activities. These changes are poised to impact the delicate balance of alpine aquatic biodiversity. In this overview, we explore regional patterns of aquatic biodiversity in mountain ecosystems, highlight examples of ongoing changes to alpine waterscapes, and examine the potential consequences for the species and biodiversity of these habitats.