Water is key to human life, both biophysically and socioculturally. Having long been regarded in anthropology as a circumstantial backdrop to human society and culture, water—alongside other nonhuman substances and beings—has received growing attention as a material with specific potentials and histories in the 21st century. This research explores the fundamental connectivity and relationality of water, through which social relations and hydrological flows are often two sides of the same coin, shaping and transforming each other. Watery materiality is frequently characterized by movement and instability, defying control but also intersecting with other social and material processes to create ever new arrangements. Water practices, infrastructures, and experiences participate in the formation and transformation of spaces and landscapes, and may inspire novel theoretical insights on meaning-making, kinship, learning, and space, among other topics. Water’s valuation and the tensions that arise regarding how to govern it emerge in part from its material properties. Ongoing discussions explore the links between these properties, water infrastructures, unequal distribution, and political power. Watery materiality is not a single thing, but has multiple manifestations, including saltwater, ice, and humidity. Some scholars therefore propose studying water and materiality in terms of various forms of wetness or amphibious processes. Research into water and materiality suggests that the material world consists of open processes rather than of fixed objects, and that water’s multiple manifestations and flows actively participate in shaping human lives.